Many people play table tennis.You can also call it Ping-Pong.It is a fun game.How do you play?You need a table tennis table with a net in the middle.You also need a Ping-Pong ball,some paddles and a friend.First,hit t...Many people play table tennis.You can also call it Ping-Pong.It is a fun game.How do you play?You need a table tennis table with a net in the middle.You also need a Ping-Pong ball,some paddles and a friend.First,hit the ball with your paddle.The ball goes over the net.Then your friend hits it back to you.Then you hit it again.The ball can move quickly!So sometimes you miss it.展开更多
We introduce an attack scheme for eavesdropping freely the ping-pong quantum communication protocol proposed by Bostrǒm and Felbinger [Phys. Rev. Left. 89, 187902 （2002）] in a noise channel. The vicious eavesdroppe...We introduce an attack scheme for eavesdropping freely the ping-pong quantum communication protocol proposed by Bostrǒm and Felbinger [Phys. Rev. Left. 89, 187902 （2002）] in a noise channel. The vicious eavesdropper, Eve, intercepts and measures the travel photon transmitted between the sender and the receiver. Then she replaces the quantum signal with a multi-photon signal in the same state, and measures the returned photons with the measuring basis, with which Eve prepares the fake signal except for one photon. This attack increases neither the quantum channel losses nor the error rate in the sampling instances for eavesdropping check. It works for eavesdropping the secret message transmitted with the ping-pong protocol. Finally, we propose a way for improving the security of the ping-pong protocol.展开更多
In order to transmit the secure messages,a deterministic secure quantum direct communication protocol,called the "Ping-pong"protocol was proposed by Bostrm and Felbinger [Phys.Rev.Lett.89,187902(2002) ].But ...In order to transmit the secure messages,a deterministic secure quantum direct communication protocol,called the "Ping-pong"protocol was proposed by Bostrm and Felbinger [Phys.Rev.Lett.89,187902(2002) ].But the protocol was proved to have many vulnerabilities,and can be attacked by eavesdroppers.To overcome the problem,an improved security detection strategy which inserts the | 0〉,| 1〉,|+〉and |-〉particles into the messages as the decoy particles randomly in the"Ping-pong"protocol is presented.During the security analysis,the method of the entropy theory is introduced,and three detection strategies are compared quantitatively by using the constraint between the information which eavesdroppers can obtain and the interference introduced.Because of the presence of the trap particles |+〉and |-〉,the detection rate will be no less than 25% when Eve attacks the communication.The security analysis result shows that the efficiency of eavesdropping detection in the presented protocol is higher than the other two,so the detection strategy in the protocol can ensure that the "Ping-pong"protocol is more secure.展开更多
A kind of turbo joint detection scheme based on parallel interference cancellation （PIC） is studied; then, the eigenvalues of iteration matrix is deeply analyzed for studying the ping-pong effects in PIC JD and the ...A kind of turbo joint detection scheme based on parallel interference cancellation （PIC） is studied; then, the eigenvalues of iteration matrix is deeply analyzed for studying the ping-pong effects in PIC JD and the corresponding compensation approach is introduced. Finally, the proposed algorithm is validated through computer simulation in TDD CDMA uplink transmission. The result shows that the ping-pong effects are almost avoided completely in the presence of the compensation scheme, and system performance is greatly improved.展开更多
Computational based cryptography might not guarantee long term security if computational algorithms, computers, and so on are made remarkable progress. Therefore, quantum cryptography with unconditionally security att...Computational based cryptography might not guarantee long term security if computational algorithms, computers, and so on are made remarkable progress. Therefore, quantum cryptography with unconditionally security attracts attention. In this paper, we consider security of a two-way quantum key distribution protocol, so called Ping-Pong protocol. As a result, we introduce not only robustness but also a different information disturbance theorem, which denotes a trade-off relationship between information gain for an eavesdropper and error rate, from the related works for an attack model.展开更多
We describe a new tracking and predicting scheme applied to a lab-made ping pong robot. The robot has a monocular vision system comprised of a camera and a light. We propose an optimized strategy to calibrate the ligh...We describe a new tracking and predicting scheme applied to a lab-made ping pong robot. The robot has a monocular vision system comprised of a camera and a light. We propose an optimized strategy to calibrate the light center using the least square method. An ellipse fitting method is used to precisely locate the center of ball and shadow on the captured image. After the triangulation of the ball position in the world coordinates, a tracking algorithm based on a Kalman filter outputs an accurate estimation of the flight states including the ball position and velocity. Furthermore, a neural network model is constructed and trained to predict the following flight path. Experimental results show that this scheme can achieve a good predicting precision and success rate of striking an incoming ball. The robot can achieve a success rate of about 80% to return a flight ball of 5 m/s to the opposite court.展开更多
The School of Chinese Medicine, the University of Hong Kong has organized the 7th Pong Ding Yuen International Symposium on Traditional Chinese Medicine cum the 10th Anniversary of the Full-time Bachelor of Chinese Me...The School of Chinese Medicine, the University of Hong Kong has organized the 7th Pong Ding Yuen International Symposium on Traditional Chinese Medicine cum the 10th Anniversary of the Full-time Bachelor of Chinese Medicine Programme on 1 December, 2012, and 2 December, 2012, in Li Ka Shing Faculty of Medicine, the University of Hong Kong.展开更多
文摘Many people play table tennis.You can also call it Ping-Pong.It is a fun game.How do you play?You need a table tennis table with a net in the middle.You also need a Ping-Pong ball,some paddles and a friend.First,hit the ball with your paddle.The ball goes over the net.Then your friend hits it back to you.Then you hit it again.The ball can move quickly!So sometimes you miss it.
基金Project supported by the National Natural Science Foundation of China （Grant No 10604008） and the Beijing Education Committee （Grant No XK100270454）.
文摘We introduce an attack scheme for eavesdropping freely the ping-pong quantum communication protocol proposed by Bostrǒm and Felbinger [Phys. Rev. Left. 89, 187902 （2002）] in a noise channel. The vicious eavesdropper, Eve, intercepts and measures the travel photon transmitted between the sender and the receiver. Then she replaces the quantum signal with a multi-photon signal in the same state, and measures the returned photons with the measuring basis, with which Eve prepares the fake signal except for one photon. This attack increases neither the quantum channel losses nor the error rate in the sampling instances for eavesdropping check. It works for eavesdropping the secret message transmitted with the ping-pong protocol. Finally, we propose a way for improving the security of the ping-pong protocol.
基金supported by Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No.20060013007National Natural Science Foundation of Beijing under Grant No.4092029National Natural Science Foundation of China under Grant No.60873001
文摘In order to transmit the secure messages,a deterministic secure quantum direct communication protocol,called the "Ping-pong"protocol was proposed by Bostrm and Felbinger [Phys.Rev.Lett.89,187902(2002) ].But the protocol was proved to have many vulnerabilities,and can be attacked by eavesdroppers.To overcome the problem,an improved security detection strategy which inserts the | 0〉,| 1〉,|+〉and |-〉particles into the messages as the decoy particles randomly in the"Ping-pong"protocol is presented.During the security analysis,the method of the entropy theory is introduced,and three detection strategies are compared quantitatively by using the constraint between the information which eavesdroppers can obtain and the interference introduced.Because of the presence of the trap particles |+〉and |-〉,the detection rate will be no less than 25% when Eve attacks the communication.The security analysis result shows that the efficiency of eavesdropping detection in the presented protocol is higher than the other two,so the detection strategy in the protocol can ensure that the "Ping-pong"protocol is more secure.
文摘A kind of turbo joint detection scheme based on parallel interference cancellation （PIC） is studied; then, the eigenvalues of iteration matrix is deeply analyzed for studying the ping-pong effects in PIC JD and the corresponding compensation approach is introduced. Finally, the proposed algorithm is validated through computer simulation in TDD CDMA uplink transmission. The result shows that the ping-pong effects are almost avoided completely in the presence of the compensation scheme, and system performance is greatly improved.
文摘Computational based cryptography might not guarantee long term security if computational algorithms, computers, and so on are made remarkable progress. Therefore, quantum cryptography with unconditionally security attracts attention. In this paper, we consider security of a two-way quantum key distribution protocol, so called Ping-Pong protocol. As a result, we introduce not only robustness but also a different information disturbance theorem, which denotes a trade-off relationship between information gain for an eavesdropper and error rate, from the related works for an attack model.
基金Project supported by the National High-Tech Research and Development Program (863) of China (No. 2008AA042602)the Fundamental Research Funds for the Central Universities of China (No. KYJD09035)
文摘We describe a new tracking and predicting scheme applied to a lab-made ping pong robot. The robot has a monocular vision system comprised of a camera and a light. We propose an optimized strategy to calibrate the light center using the least square method. An ellipse fitting method is used to precisely locate the center of ball and shadow on the captured image. After the triangulation of the ball position in the world coordinates, a tracking algorithm based on a Kalman filter outputs an accurate estimation of the flight states including the ball position and velocity. Furthermore, a neural network model is constructed and trained to predict the following flight path. Experimental results show that this scheme can achieve a good predicting precision and success rate of striking an incoming ball. The robot can achieve a success rate of about 80% to return a flight ball of 5 m/s to the opposite court.
文摘The School of Chinese Medicine, the University of Hong Kong has organized the 7th Pong Ding Yuen International Symposium on Traditional Chinese Medicine cum the 10th Anniversary of the Full-time Bachelor of Chinese Medicine Programme on 1 December, 2012, and 2 December, 2012, in Li Ka Shing Faculty of Medicine, the University of Hong Kong.
