The concept of dual image reversible data hiding（DIRDH） is the technique that can produce two camouflage images after embedding secret data into one original image.Moreover,not only can the secret data be extracted ...The concept of dual image reversible data hiding（DIRDH） is the technique that can produce two camouflage images after embedding secret data into one original image.Moreover,not only can the secret data be extracted from two camouflage images but also the original image can be recovered.To achieve high image quality,Lu et al.＇s method applied least-significant-bit（LSB） matching revisited to DIRDH.In order to further improve the image quality,the proposed method modifies LSB matching revisited rules and applies them to DIRDH.According to the experimental results,the image quality of the proposed method is better than that of Lu et al.＇s method.展开更多
中东Z油田一开井段井眼尺寸大、井段长、地质条件复杂、钻头选型不合理,探井一般需要20多只钻头才能完钻,钻井周期长、成本高,严重影响全井的建井周期和油田的大规模开发。利用测井数据,使用地层可钻性模型预测了一开井段的地层可钻性剖...中东Z油田一开井段井眼尺寸大、井段长、地质条件复杂、钻头选型不合理,探井一般需要20多只钻头才能完钻,钻井周期长、成本高,严重影响全井的建井周期和油田的大规模开发。利用测井数据,使用地层可钻性模型预测了一开井段的地层可钻性剖面,显示出该地层可钻性波动频繁、软硬交错显著、非均质性强。在此基础上设计了将强稳定性、攻击性和水利设计相结合的个性化609.6 mm MS1963UV型PDC钻头。在后续现场试验中,该型钻头突破性地实现了1只牙轮钻头+1只PDC钻头钻完一开井段,提速最高达109.77%,钻头每米成本降幅最高达32.13%。实践证明,区块可钻性预测结果较为符合实际,个性化设计的PDC钻头能够很好地适应目标井段地层,为进一步优化改进钻头设计和Z油田的持续提速提效提供了有益的参考。展开更多
With the development of current electronic technology, numerous high-speed data acquisition systems provide a variety of potential benefits. This article describes a high-speed data acquisition system which consists o...With the development of current electronic technology, numerous high-speed data acquisition systems provide a variety of potential benefits. This article describes a high-speed data acquisition system which consists of ECL logic and TTL logic devices, samples and stores data with a 1 GHz clock. This system is accomplished easily and works stably. A performance test of this system has been undertaken and the results show that the effective number of bits （ENOB） is more than 6.5 bits.展开更多
Lossless data hiding can restore the original status of cover media after embedded secret data are extracted. In 2010, Wang et al. proposed a lossless data hiding scheme which hides secret data in vector quantization ...Lossless data hiding can restore the original status of cover media after embedded secret data are extracted. In 2010, Wang et al. proposed a lossless data hiding scheme which hides secret data in vector quantization （VQ） indices, but the encoding strategies adopted by their scheme expand the final codestream. This paper designs four embedding and encoding strategies to improve Wang et aL＇s scheme. The experiment result of the proposed scheme compared with that of the Wang et aL＇s scheme reduces the bit rates of the final codestream by 4.6% and raises the payload by 1.09% on average.展开更多
This paper presents a description and performance evaluation of a new bit-level, lossless, adaptive, and asymmetric data compression scheme that is based on the adaptive character wordlength （ACW（n）） algorithm. Th...This paper presents a description and performance evaluation of a new bit-level, lossless, adaptive, and asymmetric data compression scheme that is based on the adaptive character wordlength （ACW（n）） algorithm. The proposed scheme enhances the compression ratio of the ACW（n） algorithm by dividing the binary sequence into a number of subsequences （s）, each of them satisfying the condition that the number of decimal values （d） of the n-bit length characters is equal to or less than 256. Therefore, the new scheme is referred to as ACW（n, s）, where n is the adaptive character wordlength and s is the number of subsequences. The new scheme was used to compress a number of text files from standard corpora. The obtained results demonstrate that the ACW（n, s） scheme achieves higher compression ratio than many widely used compression algorithms and it achieves a competitive performance compared to state-of-the-art compression tools.展开更多
基金supported by MOST under Grants No.105-2410-H-468-010 and No.105-2221-E-468-019
文摘The concept of dual image reversible data hiding（DIRDH） is the technique that can produce two camouflage images after embedding secret data into one original image.Moreover,not only can the secret data be extracted from two camouflage images but also the original image can be recovered.To achieve high image quality,Lu et al.＇s method applied least-significant-bit（LSB） matching revisited to DIRDH.In order to further improve the image quality,the proposed method modifies LSB matching revisited rules and applies them to DIRDH.According to the experimental results,the image quality of the proposed method is better than that of Lu et al.＇s method.
文摘中东Z油田一开井段井眼尺寸大、井段长、地质条件复杂、钻头选型不合理,探井一般需要20多只钻头才能完钻,钻井周期长、成本高,严重影响全井的建井周期和油田的大规模开发。利用测井数据,使用地层可钻性模型预测了一开井段的地层可钻性剖面,显示出该地层可钻性波动频繁、软硬交错显著、非均质性强。在此基础上设计了将强稳定性、攻击性和水利设计相结合的个性化609.6 mm MS1963UV型PDC钻头。在后续现场试验中,该型钻头突破性地实现了1只牙轮钻头+1只PDC钻头钻完一开井段,提速最高达109.77%,钻头每米成本降幅最高达32.13%。实践证明,区块可钻性预测结果较为符合实际,个性化设计的PDC钻头能够很好地适应目标井段地层,为进一步优化改进钻头设计和Z油田的持续提速提效提供了有益的参考。
文摘With the development of current electronic technology, numerous high-speed data acquisition systems provide a variety of potential benefits. This article describes a high-speed data acquisition system which consists of ECL logic and TTL logic devices, samples and stores data with a 1 GHz clock. This system is accomplished easily and works stably. A performance test of this system has been undertaken and the results show that the effective number of bits （ENOB） is more than 6.5 bits.
基金supported by the National Science Council,Taiwan under Grant No.NSC 99-2221-E-324-040-MY2
文摘Lossless data hiding can restore the original status of cover media after embedded secret data are extracted. In 2010, Wang et al. proposed a lossless data hiding scheme which hides secret data in vector quantization （VQ） indices, but the encoding strategies adopted by their scheme expand the final codestream. This paper designs four embedding and encoding strategies to improve Wang et aL＇s scheme. The experiment result of the proposed scheme compared with that of the Wang et aL＇s scheme reduces the bit rates of the final codestream by 4.6% and raises the payload by 1.09% on average.
文摘This paper presents a description and performance evaluation of a new bit-level, lossless, adaptive, and asymmetric data compression scheme that is based on the adaptive character wordlength （ACW（n）） algorithm. The proposed scheme enhances the compression ratio of the ACW（n） algorithm by dividing the binary sequence into a number of subsequences （s）, each of them satisfying the condition that the number of decimal values （d） of the n-bit length characters is equal to or less than 256. Therefore, the new scheme is referred to as ACW（n, s）, where n is the adaptive character wordlength and s is the number of subsequences. The new scheme was used to compress a number of text files from standard corpora. The obtained results demonstrate that the ACW（n, s） scheme achieves higher compression ratio than many widely used compression algorithms and it achieves a competitive performance compared to state-of-the-art compression tools.
