• Computers and Concrete
• /
• v.27 no.1
• /
• pp.63-71
• /
• 2021

In this study, a new stopping criterion, called "backward controlled stopping criterion" (BCSC), was proposed to be used in Genetic Algorithms. In the study, the available stopping citeria; adaptive stopping citerion, evolution time, fitness threshold, fitness convergence, population convergence, gene convergence, and developed stopping criterion were applied to the following four comparison problems; high strength concrete mix design, pre-stressed precast concrete beam, travelling salesman and reinforced concrete deep beam problems. When completed the analysis, the developed stopping criterion was found to be more accomplished than available criteria, and was able to research a much larger area in the space design supplying higher fitness values.

• Proceedings of the IEEK Conference
• /
• 2003.11c
• /
• pp.265-268
• /
• 2003

In this paper, we propose new simple and efficient stopping criteria for W-CDMA turbo decoding. The new criteria are based on the sum of logarithm of absolute extrinsic information values and the count of one-estimations calculated after each component decoder. The calculation of the proposed criteria can be made simpler by summing one of ten values without any penalty. This Proposed method can be implemented with negligible overhead and no extra memory. Simulation results on W-CDMA standard shows that the number of iterations required is reduced compared to the existing stopping criteria without degrading the BER performance. Reduced iterations and simple operations make the proposed criteria desirable for low-power turbo decoder.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.9C
• /
• pp.683-690
• /
• 2008

By using inherent stopping criteria of LDPC codes, the average number of iterations can be substantially reduced at high signal to noise ratio (SNR). However, we encounter a problem when hybrid automatic repeat request (H-ARQ) systems are applied. Frequent failures of decoding at low SNR region imply that the decoder leaches the maximum number of iterations frequently and thus the decoding complexity increases. In this paper, we propose a combination of stopping criteria using the syndrome weight of tentative codeword. By numerical analysis, it is shown that the decoding complexity of given H-ARQ system is reduced by 70-80% with the proposed algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.6A
• /
• pp.537-543
• /
• 2007

In this paper, we propose a new stopping criterion for the turbo processing (Turbo-BLAST) of MIMO-OFDM system. To reduce the high computational complexity of turbo-BLAST, it is desirable to lessen the outer-loop iteration number. In a system such as IEEE 802.16e Mobile WiMax, no CRC bits are available except the last encoding packet of a transmitted burst, so early stopping criteria without the help of CRC bits are needed. The proposed criterion counts the sign differences between received parity bits and the re-encoded parity bits from received information bits. With the tail-biting code which is accepted for IEEE 802.16e, a method that the re-encoder operates at half complexity is also proposed. Computer simulations show that the proposed stopping criterion approaches the performance of GENIE aided criterion with less average number of iterations than the other early stopping criteria.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.41 no.4
• /
• pp.11-16
• /
• 2004

A simple stopping criterion for iterative decoding based on min-sum processing is presented. While most stopping criteria suggested in the literature, are based on Cross Entropy (CE) and its simplification, the proposed stopping criterion is to check if a decoded sequence is a valid codeword along the encoder trellis structure. This new stopping criterion requires less computational complexity and saves mem4)ry compared to the conventional stopping rules. The numerical results are presented on the 3GPP turbo code and a Serially Concatenated Convolutional Cods (SCCC).

• Journal of The Institute of Information and Telecommunication Facilities Engineering
• /
• v.8 no.4
• /
• pp.207-215
• /
• 2009

In recent digital communication systems, the performance of Turbo Code used as the error correction coding method depends on the interleaver size influencing the free distance determination and iterative decoding algorithms of the turbo decoder. However, some iterations are needed to get a better performance, but these processes require large time delay. Recently, methods of reducing the number of iteration have been studied without degrading original performance. In this paper, the new method combining ME (Mean Estimate) stopping criterion with SDR (sign difference ratio) stopping criterion of previous stopping criteria is proposed, and the fact of compensating each method's missed detection is verified Faster decoding realizes that reducing the number of iterative decoding about 1~2 times by adopting our proposed method into serially concatenation of both decoder. System Environments were assumed DS-CDMA forward link system with intense MAI (multiple access interference).

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2000.04b
• /
• pp.458-465
• /
• 2000

In the field of structural optimization simulated annealing (SA) algorithm has widely been adopted as an optimizer with the positive features of SA such as simplicity of the algorithm and possibility of finding global solution However, annealing process of SA algorithm based on random generator with the zeroth order structural information requires a large of number of iterations highly depending on cooling schedules and stopping criteria. In this paper, MSA algorithm is presented in the form of two phase annealing process with the effective cooling schedule and stopping criteria. With the application to optimal seismic design of steel structures, the performance of the proposed MSA algorithm has been demonstrated with respect to stability and global convergence of the algorithm

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.10 no.4
• /
• pp.183-191
• /
• 2010

In the recent digital communication systems, the performance of Turbo Code used as the error correction coding method depends on the interleaver size influencing the free distance determination and the iterative decoding algorithms of the turbo decoder. However, some iterations are needed to get a better performance, but these processes require a large time delay. Recently methods of reducing the number of iteration have been studied without degrading original performance. In this paper, the new method of combining ME (Mean Estimate) stopping criterion with SDR (sign difference ratio) stopping criterion among previous stopping criteria is proposed, and the fact of compensating each method's missed detection is verified. Faster decoding is realized that about 1~2 time iterations to reduced through adopting this method into serially concatenated both decoders. System Environments were assumed W-CDMA forward link system with intense MAI (multiple access interference).

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.41 no.9
• /
• pp.39-48
• /
• 2004

Turbo codes, whose performance in bit error rate is close to the Shannon limit, have been adopted as a part of standard for the third-generation high-speed wireless data services. Iterative Turbo decoding results in decoding delay and high power consumption. As wireless communication systems can only use limited power supply, low power design techniques are essential for mobile device implementation. This paper proposes new effective criteria for stopping the iteration process in turbo decoding to reduce power consumption. By setting two stopping criteria, decodable threshold and undecodable threshold, we can effectively reduce the number of decoding iterations with only negligible error-correcting performance degradation. Simulation results show that the number of unsuccessful error-correction can be reduced by 89% and the number of decoding iterations can be reduced by 29% on the average among 12500 simulations when compared with those of an existing typical method.

• Journal of Navigation and Port Research
• /
• v.29 no.7
• /
• pp.595-601
• /
• 2005

The IMO manoeuvrability standard was established for preventing sea accidents such as collisions and strandings due to the lack of manoeuvrability. The standard of ship manoeuvrability enforced by resolution MSC.l37(76) has been applied to vessels of 100m or more in length and all chemical tankers and gas carriers regardless of the length, which were constructed on or after 1 July 1994. The IMO manoeuvrability standard is able to be divided into three kinds as followings; (1) Turning capability standard: Estimated values in design stage are to be certified by turning circle test of the actual vessel. (2) Course keeping quality standard : Estimated values in design stage are to be certified by 10 deg. and 20 deg. zig-zag tests of the actual vessel. (3) Shortest stopping distance standard : Estimated value in design stage is to be certified by the shortest stopping distance tested by the actual vessel. In this paper, the authors verified the criteria of IMO manoeuvrability standard comparing them with the values resulted from sea trial tests of various kinds of actual vessels and examined separately the validity of all criteria of the standard.