The paper intfoduces a PC-DSP based real-time digital simulator which is portable in size and aimed at the closed-loop testing of various types of protective relays for their design and application. The simulator can ...The paper intfoduces a PC-DSP based real-time digital simulator which is portable in size and aimed at the closed-loop testing of various types of protective relays for their design and application. The simulator can be widely used in not only concerning utilities but also manufacturers and research / certification institutes because of its many functions. The hardware architecture and software implementation of the simulator are described. The main features and functions of the simulator are also展开更多
With widespread use of relational database in various real-life applications,maintaining integrity and providing copyright protection is gaining keen interest of the researchers.For this purpose,watermarking has been ...With widespread use of relational database in various real-life applications,maintaining integrity and providing copyright protection is gaining keen interest of the researchers.For this purpose,watermarking has been used for quite a long time.Watermarking requires the role of trusted third party and a mechanism to extract digital signatures(watermark)to prove the ownership of the data under dispute.This is often inefficient as lots of processing is required.Moreover,certain malicious attacks,like additive attacks,can give rise to a situation when more than one parties can claim the ownership of the same data by inserting and detecting their own set of watermarks from the same data.To solve this problem,we propose to use blockchain technology—as trusted third party—along with watermarking for providing a means of rights protection of relational databases.Using blockchain for writing the copyright information alongside watermarking helps to secure the watermark as changing the blockchain is very difficult.This way,we combined the resilience of our watermarking scheme and the strength of blockchain technology—for protecting the digital rights information from alteration—to design and implement a robust scheme for digital right protection of relational databases.Moreover,we also discuss how the proposed scheme can also be used for version control.The proposed technique works with nonnumeric features of relational database and does not target only selected tuple or portion(subset)from the database for watermark embedding unlike most of the existing techniques;as a result,the chances of subset selection containing no watermark decrease automatically.The proposed technique employs zerowatermarking approach and hence no intentional error(watermark)is added to the original dataset.The results of the experiments proved the effectiveness of the proposed scheme.展开更多
A trusted third party introduced in watermarking protocols would decrease the security and affect the implementation of the protocols. In this paper, a new watermarking protocol with an un-trusted third party (UTTP)...A trusted third party introduced in watermarking protocols would decrease the security and affect the implementation of the protocols. In this paper, a new watermarking protocol with an un-trusted third party (UTTP) was proposed. Based on the idea of all-or-nothing disclosure of secret (ANDOS), all of the buyer, the seller and the third party didn't know the exact watermark, which was embedded in a digital content for tracing piracy. The proposed protocol provided mechanisms to trace piracy and protect customer's right. In addition, the problem that a seller colluded with UTTP to frame the buyer, namely, the conspiracy problem, could be avoided.展开更多
Controversies over the inheritance of online profiles highlight the urgent need for legislation on the status of virtual assets Recently,a woman surnamed Wang in Shenyang City,northeast China’s Liaoning Province,cont...Controversies over the inheritance of online profiles highlight the urgent need for legislation on the status of virtual assets Recently,a woman surnamed Wang in Shenyang City,northeast China’s Liaoning Province,contacted Tencent,operator of China’s most popular instant messaging展开更多
Transformer Differential and overcurrent schemes are traditionally used as main and backup protection respectively. The differential protection relay (SEL487E) has dedicated harmonic restraint function which blocks th...Transformer Differential and overcurrent schemes are traditionally used as main and backup protection respectively. The differential protection relay (SEL487E) has dedicated harmonic restraint function which blocks the relay tripping during the transformer magnetizing inrush conditions. However, the backup overcurrent relay (SEL751A) applied to the transformer protection does not have harmonic restraint element and trip the overcurrent relay during the inrush conditions. Therefore, major contribution of this research work is the developed harmonic blocking scheme for transformer which uses element (87HB) of the transformer differential relay (SEL487E) to send an IEC61850 GOOSE-based harmonic blocking signal to the backup overcurrent relay (SEL751A) to inhibit from tripping during the transformer magnetizing inrush current conditions. The simulation results proved that IEC61850 standard-based protection scheme is faster than the hardwired signals. Therefore, the speed and reliability of the transformer scheme are improved using the IEC61850 standard-based GOOSE applications.展开更多
文摘The paper intfoduces a PC-DSP based real-time digital simulator which is portable in size and aimed at the closed-loop testing of various types of protective relays for their design and application. The simulator can be widely used in not only concerning utilities but also manufacturers and research / certification institutes because of its many functions. The hardware architecture and software implementation of the simulator are described. The main features and functions of the simulator are also
基金This project was supported by University of Jeddah under the Grant Number(UJ-02-014-ICGR).
文摘With widespread use of relational database in various real-life applications,maintaining integrity and providing copyright protection is gaining keen interest of the researchers.For this purpose,watermarking has been used for quite a long time.Watermarking requires the role of trusted third party and a mechanism to extract digital signatures(watermark)to prove the ownership of the data under dispute.This is often inefficient as lots of processing is required.Moreover,certain malicious attacks,like additive attacks,can give rise to a situation when more than one parties can claim the ownership of the same data by inserting and detecting their own set of watermarks from the same data.To solve this problem,we propose to use blockchain technology—as trusted third party—along with watermarking for providing a means of rights protection of relational databases.Using blockchain for writing the copyright information alongside watermarking helps to secure the watermark as changing the blockchain is very difficult.This way,we combined the resilience of our watermarking scheme and the strength of blockchain technology—for protecting the digital rights information from alteration—to design and implement a robust scheme for digital right protection of relational databases.Moreover,we also discuss how the proposed scheme can also be used for version control.The proposed technique works with nonnumeric features of relational database and does not target only selected tuple or portion(subset)from the database for watermark embedding unlike most of the existing techniques;as a result,the chances of subset selection containing no watermark decrease automatically.The proposed technique employs zerowatermarking approach and hence no intentional error(watermark)is added to the original dataset.The results of the experiments proved the effectiveness of the proposed scheme.
基金Supported by the National Natural Science Founda-tion of China (90304008) the Graduate Innovation Fund of XidianUniversity (05019 , 05017)the College and University Sbject ofDoctors Specific Sientific Research Foundation of China(20040701001)
文摘A trusted third party introduced in watermarking protocols would decrease the security and affect the implementation of the protocols. In this paper, a new watermarking protocol with an un-trusted third party (UTTP) was proposed. Based on the idea of all-or-nothing disclosure of secret (ANDOS), all of the buyer, the seller and the third party didn't know the exact watermark, which was embedded in a digital content for tracing piracy. The proposed protocol provided mechanisms to trace piracy and protect customer's right. In addition, the problem that a seller colluded with UTTP to frame the buyer, namely, the conspiracy problem, could be avoided.
文摘Controversies over the inheritance of online profiles highlight the urgent need for legislation on the status of virtual assets Recently,a woman surnamed Wang in Shenyang City,northeast China’s Liaoning Province,contacted Tencent,operator of China’s most popular instant messaging
基金funded by the National Research Foundation(NRF)THRIP grant TP2011061100004,ESKOM TESP(Capacitor Banks Placement)ESKOM Academy of Learning,ESKOM Power Plants Energy Institute(EPPEI)and CPUT(Prestigious Project)grant for the Centre of Substation Automation and Energy Management Systems(CSAEMS)development and growth.
文摘Transformer Differential and overcurrent schemes are traditionally used as main and backup protection respectively. The differential protection relay (SEL487E) has dedicated harmonic restraint function which blocks the relay tripping during the transformer magnetizing inrush conditions. However, the backup overcurrent relay (SEL751A) applied to the transformer protection does not have harmonic restraint element and trip the overcurrent relay during the inrush conditions. Therefore, major contribution of this research work is the developed harmonic blocking scheme for transformer which uses element (87HB) of the transformer differential relay (SEL487E) to send an IEC61850 GOOSE-based harmonic blocking signal to the backup overcurrent relay (SEL751A) to inhibit from tripping during the transformer magnetizing inrush current conditions. The simulation results proved that IEC61850 standard-based protection scheme is faster than the hardwired signals. Therefore, the speed and reliability of the transformer scheme are improved using the IEC61850 standard-based GOOSE applications.