Efficient Early Termination Strategy for LDPC Codes in GPS Systems

By exploiting the structural features of L1C messages,a novel Early Termination( ET) strategy is proposed to speed up the decoding of low-density parity-check( LDPC) codes in the GPS system. The proposed strategy is based on the cyclic redundancy check( CRC) of the messages in the subframes 2 and 3. The simulation results show that average number of iterations of the proposed strategy is less than that of the standard ET strategy,with nearly no degradation in decoding performance. Besides,the proposed ET strategy can be efficiently implemented in a sequential or parallel manner. Thus,the proposed ET strategy is attractive for practical purposes.

On a Flexible Loan Repayment Method Depending on Borrower's Asset with an Early Termination Clause

Aiming at the problem that the asset’s fluctuation influences the borrower’s repayment ability,a loan with a new and flexible repayment method is designed,which depends on the asset value of the borrower.The repayment method can reduce the loan default probability,but it causes the uncertainty of the pay off time.Because the repayment term is related to the regular repayment amount in this method,a boundary for the regular repayment amount is set up in order to avoid too long repayment term.This will balance the benefit of borrowers and lenders and improve the applicability of this method.By establishing a mathematical model of the residual value of the loan,this model can be transformed into an initial-boundary problem of a partial differential equation.The analytic solution and the expected time to pay off the loan are obtained.Finally,numerical analysis are shown.

Early termination strategy of HEVC based on statistical models

High efficiency video coding(HEVC)uses half of the bitrate compared to H.264/advanced video coding(AVC)for encoding the same sequence with similar quality.Because of the advanced hierarchical structures of coding units(CUs),predicting units(PUs),and transform units(TUs),HEVC can better adapt when encoding full high definition(HD)and ultra high definition(UHD)videos.At the expense of encoding efficiency,the complexity of HEVC sharply increases compared to H.264/AVC,mainly due to its quad-tree structure that splits pictures.In this study,the probability distribution,which is generated by a rate distortion optimizing(RDO)cost,is analyzed.Then,an early terminating method is proposed to decrease the complexity of the HEVC based on probability distributions.The experiment shows that the coding time is reduced by 44.9%for HEVC intra coding,at the cost of a 0.61%increase in the Bj?ntegaard delta rate(BD-rate),on average.

Parity-check and G-matrix based intelligent early stopping criterion for belief propagation decoder for polar codes

The error correction performance of Belief Propagation(BP)decoding for polar codes is satisfactory compared with the Successive Cancellation(SC)decoding.Nevertheless,it has to complete a fixed number of iterations,which results in high computational complexity.This necessitates an intelligent identification of successful BP decoding for early termination of the decoding process to avoid unnecessary iterations and minimize the computational complexity of BP decoding.This paper proposes a hybrid technique that combines the“paritycheck”with the“G-matrix”to reduce the computational complexity of BP decoder for polar codes.The proposed hybrid technique takes advantage of the parity-check to intelligently identify the valid codeword at an early stage and terminate the BP decoding process,which minimizes the overhead of the G-matrix and reduces the computational complexity of BP decoding.We explore a detailed mechanism incorporating the parity bits as outer code and prove that the proposed hybrid technique minimizes the computational complexity while preserving the BP error correction performance.Moreover,mathematical formulation for the proposed hybrid technique that minimizes the computation cost of the G-matrix is elaborated.The performance of the proposed hybrid technique is validated by comparing it with the state-of-the-art early stopping criteria for BP decoding.Simulation results show that the proposed hybrid technique reduces the iterations by about 90%of BP decoding in a high Signal-to-Noise Ratio(SNR)(i.e.,3.5~4 dB),and approaches the error correction performance of G-matrix and conventional BP decoder for polar codes.

Effect of Low Dose of Mifeprostone in Capsules combined with Misoprostol on Termination of Early Pregnancy

ve In this double-blind randomized trial, we compare the effect of 75 mg mifeprostone in capsules on termination of early pregnancy was compared with that of 150 mg in tablets combined with misoprostol.

Clinical Pharmacodynamics of Mifepristone（RU486） for Termination of Early－Pregnancy

Twenty-four healthy female volunteers with amenorrhea for seven weeks or less.asking for legal termination of pregnancy were recruited and divided into 4 groups (6 each). The subjects were orally administered with RU486 of 50mg (Group Ⅰ). 50mg Q12hx 6 (GrouP Ⅱ),200mg(GrouP Ⅲ)or 600mg(Group Ⅳ).Vacuum aspiration(GrouP Ⅰ)or Methyl Carprost Suppository(PGOS 1.0mg)(GrouP Ⅱ-Ⅳ)was given 72h after the firsl dose followed by a 6--hour medl'cal survel'llance.Blood samples were collected on day 1-6,8,15,43 to measure the serum levels of β-hCG,E2,P,PRL,ACTH, Cortisol,T3,T4 and TSH in each subject.The results showed that no significant dose-effect relationship was observed in terms of clinical efficacy,vaginal bleeding or side effects.All four groups shared the same tendency of changes in serum levels of β-hCG,E2 and P.β-hCG levels increased by 50-100% (P<0.01)24h prior to treatment,and continued ic ipcrease following lreatment until the sac expulsion.EZ levels l'n each group reinal'ned higher than pre-treatment values with the gradual decline in P levels.β-hCG,E2 and P decreased drastically after abortion,levels of β-hCG,E2,P on day 5 were only 35-60% (P<0.01),32-46%(P<0.01)and 30-56%(P<0.01)of those on day 4 respectively.The mean PRL levels on day 2-4 in each group increased obviously but declined gradually following the sac ex.pulsion.During treatment,the respective cortisol levels increased dramatically,the average levels ofcortisol on day 2-4 were 30-40%(P<0.05) l'n GrouP Ⅰ-Ⅲ and 60%(P< 0.01) in Group Ⅳ higher as compared with day 1 values, while decreased rapidly af ter termination of pregnancy as indicated that cortisol levels on day 5 were only 67-81%(P<0.05) of those on day 4.The changes in ACTH,T3,T4,TSH levels were of no statistic sigulAance(P>0.05).This study indicated that RU486 has no dose-effect relationship when used for interruption of early pregnancy and its main action site seems neither in ovary nor in villi.It has some effects on pituitary-adrenal axis,especially in large dosage,however,it has no obvious impact on pituilary-thyroid axis.It seems that the changes in PRL serum levels were directly due to the drug itsed ifs clinical significance should be further studied.

Fast motion estimation algorithm for H.264/AVC based on centered prediction

H.264/AVC video coding standard can achieve roughly half of the bit-savings over MPEG2 and MPEG4 for a given quality. However, this comes at a cost in considerably increased complexity at the encoder and thus increases the difficulty in hardware implementation. The high redundancy that exists between the successive frames of a video sequence makes it possible to achieve a high data compression ratio. Motion estimation （ME） plays an important role in motion compensated video coding. A fast motion estimation algorithm for H.264/AVC is proposed based on centered prediction, called centered prediction based fast mixed search algorithm （CPFMS）. It makes use of the spatial and temporal correlation in motion vector （MV） fields and feature of all-zero blocks to accelerate the searching process. With the initialized searching point prediction, adaptive search window changing and searching direction decision, CPFMS is provided to reduce computation in block-matching process. The experimental results show that the speed of CPFMS is nearly 12 times of FS with a negligible peak signal-noise ratio （PSNR） loss. Also, the efficiency of CPFMS outperforms some popular fast algorithms such as hybrid unsymmetrical cross multi-hexagongrid search and a novel multidirectional gradient descent search evidently.

Improved encoding structure and decoding algorithms for spinal codes

To improve the error correction performance, an innovative encoding structure with tail-biting for spinal codes is designed. Furthermore, an adaptive forward stack decoding(A-FSD) algorithm with lower complexity for spinal codes is proposed. In the A-FSD algorithm, a flexible threshold parameter is set by a variable channel state to narrow the scale of nodes accessed. On this basis, a new decoding method of AFSD with early termination(AFSD-ET) is further proposed. The AFSD-ET decoder not only has the ability of dynamically modifying the number of stored nodes, but also adopts the early termination criterion to curtail complexity. The complexity and related parameters are verified through a series of simulations. The simulation results show that the proposed spinal codes with tail-biting and the AFSD-ET decoding algorithms can reduce the complexity and improve the decoding rate without sacrificing correct decoding performance.

Hemizygous deletion in the OTC gene results in ornithine transcarbamylase deficiency:A case report

BACKGROUND Ornithine transcarbamylase deficiency(OTCD)is a common ornithine cycle disorder,and OTC gene variation is the main pathogenic factor of this disease.This study explored and validated a variant in the OTC gene.CASE SUMMARY The neonate exhibited high blood ammonia,lactic acid,and homocysteine levels on the fifth day after birth.A novel deletion variant in the OTC gene[NM_000531.5,c.970_979delTTCCCAGAGG,p.Phe324GlnfsTer16]was uncovered by exome sequencing.The variant caused a protein-coding frameshift and resulted in early translation termination at the 16th amino acid after the variant site.CONCLUSION Our results provide a novel pathogenic variant in OTC and related clinical features for further OTCD screening and clinical consultation.