• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.1
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• pp.83-91
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• 1993

In the digital transmission system, cyclic redundancy check(CRC) code is widely used because it is easy to be implemented and has good performance in error detection. CRC code generator consists of several shift registers and modulo 2 adders. After manipulation of input data stream in the encoder, the remaining value of shift registers becomes CRC code. At the receiving side, error can be detected and corrected by CRC codes immediately transmitted after data stream. But, in the high speed system such as an A TM switch, it is difficult to implement the serial CRC encoder because of speed limitation of available semiconductor devices. In this paper, we propose the efficient parallel CRC encoder and syndrome calculator to solve the speed problem in implementing these functions using the existing semiconductor technology.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.3C
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• pp.195-204
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• 2007

The cyclic redundancy check(CRC) code used to decide retransmission request in hybrid automatic repeat request(HRAQ) system can also be used to stop iterative decoding of turbo code if it is used as an error correcting code(ECC) of HARQ system. Thus a scheme to use CRC code for both iteration stop and repeat request in the HARQ system with turbo code based on the standard of cdma 2000 system is proposed in this paper. At first, the optimum CRC code which has the minimum length without performance degradation due to undetected errors is found. And the most appropriate turbo encoder structure is also suggested. As results, it is shown that at least 32-bit CRC code should be used and a turbo code with 3 constituent encoders is considered to be the most appropriate one.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.14 no.6
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• pp.590-603
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• 1989

In tnis paper, the CRC-CCITT code and primitive polynomial CRC code are selected for analysing error detecting performance. However, general formulas for obtaining the weight distribution of these two CRC codes are not so far dericed. So, a new method for calculating the weight distribution of the shortened cyclic Hamming code is presented and an undetected error probability of these two codes is obtained when used in cell of ATM for broadband ISDN user-network interface. Consequently, we show that CRC code too much does affect its error detection performance. All the computer simulation is performed by IBM PC/AT.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.6A
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• pp.438-449
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• 2012

This paper presents new CRC-p codes for VHF band maritime wireless communication system based on performance analysis of various CRC codes. For this purpose, we firstly describe the method of determination of undetected error probability and minimum Hamming distance according to variation of CRC codeword length. By using the fact that the dual code of cyclic Hamming code and primitive BCH code become maximum length codes, we present an algorithm for computation of undetected error probability and minimum Hamming distance where the concept of simple hardware that is consisted of linear feedback shift register is utilized to compute the weight distribution of CRC codes. We also present construction of transmit data frame of VHF band maritime wireless communication system and specification of major communication parameters. Finally, new optimal CRC-p codes are presented based on the simulation results of undetected error probability and minimum Hamming distance using the various generator polynomials of CRC codes, and their performances are evaluated with simulation results of bit error rate based on the Rician maritime channel model and ${\pi}$/4-DQPSK modulator.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2003.06a
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• pp.205-208
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• 2003

In this paper, we realized radio controller with Convolution code and CRC code to solve the wired and wireless controller's problem that is present industry spot. We used microprocessor as a controller, and analyzed testing data with and without Convolution code. Convolution code of constraint length k=3, symbols rate 1/2 dramatically improves the radio controller's fidelity, and the number of CRC bit is 16bit(2byte) and the polynomial of /Χ$^{15}$ ＋Χ$^{2}$＋1 is used.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.4
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• pp.165-172
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• 2002

In the next generation mobile communications, powerful channel coding is essential in order to obtain high quality multimedia services. Turbo code can achieve good error performance by iterative decoding, but more iterations result in additional computational complexity and delay. Thus, a method to reduce the number of iterations without additional performance degradation is needed. Turbo code with CRC is known to be the most efficient method to reduce the number of iterations. In this scheme, the performance may be degraded by the edge-effect like the conventional turbo code without CRC. In this paper, a method to eliminate the edge-effect is proposed by adopting D-parameter to the conventional s-random interleaver. As results of simulation, the edge-effect of the turbo code with CRC is shown to be successfully eliminated by using the new interleaver designed with D-parameter.

• Journal of IKEEE
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• v.18 no.4
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• pp.509-516
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• 2014

CRC feature in a high-speed semiconductor memory devices such as DDR4/GDDR5 increases the data reliability. Conventional CRC method have a massive area overhead and long delay time. It leads to insufficient internal timing margins for CRC calculation. This paper, presents a CRC code method that provides error detection and a real-time matrix type CRC. If there are errors in the data, proposed method can alert to the system in a real-time manner. Compare to the conventional method(XOR 6 stage ATM-8 HEC code), the proposing method can improve the error detection circuits up to 60% and XOR stage delay by 33%. Also the real-time error detection scheme can improve the error detection speed to agerage 50% for the entire data bits(UI0~UI9).

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.2
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• pp.333-340
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• 2018

This paper introduces a BCH code decoder using parallel CRC(: Cyclic Redundancy Check) generation. Using a conventional parallel syndrome generator with a LFSR(: Linear Feedback Shift Register), it takes up a lot of space for a short code. The proposed decoder uses the parallel CRC method that is widely used to compute the checksum. This scheme optimizes the a syndrome generator in the decoder by eliminating redundant xor operation compared with the parallel LFSR and thus minimizes chip area and propagation delay. In simulation results, the proposed decoder has accomplished propagation delay reduction of 2.01 ns as compared to the conventional scheme. The proposed decoder has been designed and synthesized in $0.35-{\mu}m$ CMOS process.

• Journal of Cancer Prevention
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• v.23 no.4
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• pp.183-190
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• 2018

Background: As the number of big-cohort studies increases, validation becomes increasingly more important. We aimed to validate administrative database categorized as colorectal cancer (CRC) by the International Classification of Disease (ICD) 10th code. Methods: Big-cohort was collected from Clinical Data Warehouse using ICD 10th codes from May 1, 2003 to November 30, 2016 at Seoul National University Bundang Hospital. The patients in the study group had been diagnosed with cancer and were recorded in the ICD 10th code of CRC by the National Health Insurance Service. Subjects with codes of inflammatory bowel disease or tuberculosis colitis were selected for the control group. For the accuracy of registered CRC codes (C18-21), the chart, imaging results, and pathologic findings were examined by two reviewers. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for CRC were calculated. Results: A total of 6,780 subjects with CRC and 1,899 control subjects were enrolled. Of these patients, 22 subjects did not have evidence of CRC by colonoscopy, computed tomography, magnetic resonance imaging, or positron emission tomography. The sensitivity and specificity of hospitalization data for identifying CRC were 100.00% and 98.86%, respectively. PPV and NPV were 99.68% and 100.00%, respectively. Conclusions: The big-cohort database using the ICD 10th code for CRC appears to be accurate.

• Journal of Preventive Medicine and Public Health
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• v.56 no.4
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• pp.312-318
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• 2023

Objectives: We reviewed the operational definitions of colorectal cancer (CRC) from studies using the Korean National Health Insurance Service (NHIS) and compared CRC incidence derived from the commonly used operational definitions in the literature with the statistics reported by the Korea Central Cancer Registry (KCCR). Methods: We searched the MEDLINE and KoreaMed databases to identify studies containing operational definitions of CRC, published until January 15, 2021. All pertinent data concerning the study period, the utilized database, and the outcome variable were extracted. Within the NHIS-National Sample Cohort, age-standardized incidence rates (ASRs) of CRC were calculated for each operational definition found in the literature between 2005 and 2019. These rates were then compared with ASRs from the KCCR. Results: From the 62 eligible studies, 9 operational definitions for CRC were identified. The most commonly used operational definition was "C18-C20" (n=20), followed by "C18-C20 with claim code for treatment" (n=3) and "C18-C20 with V193 (code for registered cancer patients' payment deduction)" (n=3). The ASRs reported using these operational definitions were lower than the ASRs from KCCR, except for "C18-C20 used as the main diagnosis." The smallest difference in ASRs was observed for "C18-C20," followed by "C18-C20 with V193," and "C18-C20 with claim code for hospitalization or code for treatment." Conclusions: In defining CRC patients utilizing the NHIS database, the ASR derived through the operational definition of "C18-C20 as the main diagnosis" was comparable to the ASR from the KCCR. Depending on the study hypothesis, operational definitions using treatment codes may be utilized.