• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.565-568
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• 2003

This paper presents a method that can be used to reduce the decoding computational complexity in turbo codes. To reduce the decoding complexity we proposed an adaptive sliding window method which control the learning period of Viterbi sliding window method depending on channel signal to interference ratio (SIR). When received signal to interference ratio (SIR) is relatively high, we can reduce the decoding complexity without a noticeable degradation of BER performance at CDMA cellular system with power control error.

• Proceedings of the Korean Nuclear Society Conference
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• 2002.10a
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• pp.155.2-155
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• 2002

A visual environment for system analysis codes (hereinafter called "ViSA") has been developed to support code users in their input preparations, code executions, and output interpretations. ViSA provides a more convenient way for base input data generation and modification on a user-friendly basis. It also provides on-line graphical displays to give an in-depth understanding of transient thermal-hydraulic behaviors in nuclear power plants. This paper presents the main features of ViSA.

• Journal of computational fluids engineering
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• v.21 no.3
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• pp.89-97
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• 2016

In this study, direct code coupling, in which two codes share a single flow field, was conducted using 3-dimensional high resolution thermal hydraulics code, CUPID and 1-dimensional system analysis code, MARS. This approach provide the merit to use versatile capability of MARS for nuclear power plants and 3-dimensional T/H analysis capability of CUPID. Numerical Method to directly couple CUPID and MARS was described in this paper. The straight flow and manometer flow oscillation were calculated to verify conservation of coupled CUPID/MARS code in mass, momentum, and energy. This verification calculations indicates that the CUPID/MARS is coupled appropriately in numerical aspect and the coupled code can be applied to nuclear reactor thermal hydraulics after validation against integral transient experiments.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.217-221
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• 2002

In this research a Matlab/Simulink/RTW - based on the realtime control system was developed for an induction motor vector control. On the Simulink window, the control system is designed In the form of block diagrams, program codes are produced automatically with the RTW(Real Time Workshop), then a DSP c compiler complies the program codes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.7
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• pp.1374-1389
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• 1994

In this paper, a novel M-ary orthogonal CDMA scheme which utilizes time hopping codes and binary orthogonal sequences is proposed for personal communication system. Its modulated output signal has the characteristics of greater bandwidth occupancy and lower spectral density level as well. So this scheme is useful for spectrum overlay with existing narrowband communication systems which occupy current radio frequency channels. This paper investigates system characteristics through the analysis of modulated output signal power spectrum, and demonstrates the possibility of spectrum overlay.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.7
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• pp.1477-1486
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• 1997

Conventioally the decoding methods and the design of coset codes for burst synchronization and error detection have been based on the concept that slips occuring to the right or to the left with respect to a reference timing are corrected. In this paper we newly approach to the design of coset codes relying on the condition that only a single code word can exists in an observation interval, which provides an extentended view on the conventional approach. A theorem concerning the condition is presented. A combined burst synchronization and error detection system with maximum slip correction capability have been devised based on the theorem and a detection method is falsely accepted in the presented of channel errors. The false acceptance probabilities of the system are derived and its performance is analyzed through computer computation using the derived results.

• Proceedings of the IEEK Conference
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• summer
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• pp.1-4
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• 2004

We proposed a new type of timing recovery scheme to work with a system that uses BCJR (Bahl-Cocke-Jelinek-Raviv) decoding algorithm and BPSK modulation. The unknown timing offset is estimated by the modified Mueller and $M\ddot{u}ller$ estimator with the aid of the decoder. Timing offset can be acquired as soon as the symbols are received and be updated symbol by symbol. The simulation results for turbo codes whose decoder uses BCJR algorithm show a satisfactory performance even in case of severe timing jitter.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.3163-3165
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• 2000

In code division multiple access systems using all-optical signal processing, the optical multiple access interference by simultaneous multiple users degrades the system performance and eventually can limit the number of active users. To reduce the effect of the interference, error-correction codes are used in 2-dimensional FO-CDMA systems. In this paper we propose a method of applying product code to 2-dimensional FO-CDMA systems. The proposed coding scheme can correct a random error and burst errors with small redundancy to the conventional case. In result we show significant performance enhancement of the system in terms of HER, the number of active users.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.63-68
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• 1999

A 2$\frac{1}{2}$ dimensional measurement and inspection system realized on the machine tool using a touch trigger probe and measuring G codes is synthesized in this paper. Measuring G codes have been constructed according to geometric farms, precision attributes, relationships between two parts, datum hierarchies, and relevant technological data by using measuring arguments. Algorithms far calibration and compensation of measuring errors are proposed to ensure the measuring accuracy by using a laser interferometer and ring gauges. Classification of feed rates according to the objectives of movement makes it possible to reduce measuring time and also implement collision-free measurement. Experiments are conducted to verify the validity and effectiveness of proposed methods.

• Electronics and Telecommunications Trends
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• v.37 no.2
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• pp.1-10
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• 2022

Similar to present computers, quantum computers comprise quantum bits (qubits) and an operating system. However, because the quantum states are fragile, we need to correct quantum errors using entangled physical qubits with quantum error correction (QEC) codes. The combination of entangled physical qubits with a QEC protocol and its computational model are called a logical qubit and fault-tolerant quantum computation, respectively. Thus, QEC is the heart of fault-tolerant quantum computing and overcomes the limitations of noisy intermediate-scale quantum computing. Therefore, in this study, we briefly survey the status of QEC codes and the physical implementation of logical qubit over various qubit technologies. In summary, we emphasize 1) the error threshold value of a quantum system depends on the configurations and 2) therefore, we cannot set only any specific theoretical and/or physical experiment suggestion.