2021 IEEE International Conference on Recent Advances in Systems Science and Engineering (RASSE), 2021
Fragile watermarking can cause lower image quality and zero watermarking usually fails to detect ... more Fragile watermarking can cause lower image quality and zero watermarking usually fails to detect image attacks. To solve these problems, this paper proposes a novel fragile zero watermarking (FZW) method by fusing fragile watermarking and zero watermarking. The FZW method mainly includes two parts: (1) To guarantee high image quality, two least significant bits of pixel values of before-transmission and after-transmission images are extracted as image features, which are then embedded into the constructed binary original watermarking by XOR operation to generate the register watermarking and reconstructed watermarking; (2) To detect image attacks, the register watermarking and reconstructed watermarking are compared by bit-wise, and if they are same, it means that there is no attack, otherwise attacks occur. Real-time control experiments on networked inverted pendulum visual servo system platform confirm the feasibility and effectiveness of the proposed method.
Abstract Multi-stage attack is a kind of sophisticated intrusion strategy that has been widely us... more Abstract Multi-stage attack is a kind of sophisticated intrusion strategy that has been widely used for penetrating the well protected network infrastructures. To detect such attacks, state-of-the-art research advocates the use of hidden markov model (HMM). However, despite the HMM can model the relationships and dependencies among different alerts and stages for detection, they cannot handle well the stage dependencies buried in a longer sequence of alerts. In this paper, we tackle the challenge of the stages’ long-term dependency and propose a new detection solution using a sequence-to-sequence (seq2seq) model. The basic idea is to encode a sequence of alerts (i.e., detector’s observation) into a latent feature vector using a long-short term memory (LSTM) network and then decode this vector to a sequence of predicted attacking stages with another LSTM. By the encoder-decoder collaboration, we can decouple the local constraint between the observed alerts and the potential attacking stages, and thus able to take the full knowledge of all the alerts for the detection of stages in a sequence basis. By the LSTM, we can learn to “forget” irrelevant alerts and thereby have more opportunities to “remember” the long-term dependency between different stages for our sequence detection. To evaluate our model’s effectiveness, we have conducted extensive experiments using four public datasets, all of which include simulated or re-constructed samples of real-world multi-stage attacks in controlled testbeds. Our results have successfully confirmed the better detection performance of our model compared with the previous HMM solutions.
International Journal of Antennas and Propagation, 2017
A novel kind of compact dual-band quadrature patch coupler for vehicular beam-forming array is pr... more A novel kind of compact dual-band quadrature patch coupler for vehicular beam-forming array is proposed for the first time in this paper. To keep the performance of the first operating frequency 2.4 GHz (for Bluetooth Low Energy (BLE)) and generate the second operating frequency 5.9 GHz (for Dedicated Short Range Communications (DSRC)) simultaneously, complementary triangular split resonant rings (CTSRRs) and splitting gaps are employed to improve the performance of this new coupler; final size of the proposed coupler is 0.24λg (for 2.4 GHz). To validate the performance and design method of the coupler this paper proposed, a 3D model is constructed and optimized with ANSOFT HFSS firstly and then a coupler prototype is fabricated and measured. The measured results show that the amplitude unbalance (AU) is 0.54 dB and 0.44 dB for 2.4 GHz and 5.9 GHz, respectively, and the corresponding phase unbalance (PU) is 93.5 and 92 degrees, respectively.
Progress In Electromagnetics Research Letters, 2008
A novel planar omnidirectional array based on Quasi-Yagi antenna is proposed in this paper. The m... more A novel planar omnidirectional array based on Quasi-Yagi antenna is proposed in this paper. The modeling of this antenna and design method based on equivalent circuits have been developed. An eight-unit planar array has been designed, fabricated and measured. Measured results exhibit good performance of the return loss and radiation pattern in horizontal plane. The gain of the array in horizontal plane was about 0 dBi. The un-roundness of the radiation pattern in horizontal plane was about 5 dB.
Journal of Electromagnetic Waves and Applications, 2009
A compact low insertion loss vertical transition and power divider (PD) using millimeter wave cir... more A compact low insertion loss vertical transition and power divider (PD) using millimeter wave circuit/module is presented. Substrate integrated circular cavity (SICC) is employed to improve the performance of transition and PD structure. Two different D simulation tools are employed to validate the design method of the structure.
2007 International Conference on Communications, Circuits and Systems, 2007
An investigation of 94.5 GHz avalanche diode high order frequency multiplier is presented. The no... more An investigation of 94.5 GHz avalanche diode high order frequency multiplier is presented. The nonlinearity property of avalanche phenomenon has evoked great interest in high order frequency multiplication. Theoretical analysis of harmonic characters of avalanche current is outlined. In experiment 4.1 mW output power and 0.8% efficiency are obtained. Meanwhile the phase noise of 84 dBc/Hz at 10 KHz offset
2021 IEEE International Conference on Recent Advances in Systems Science and Engineering (RASSE), 2021
Fragile watermarking can cause lower image quality and zero watermarking usually fails to detect ... more Fragile watermarking can cause lower image quality and zero watermarking usually fails to detect image attacks. To solve these problems, this paper proposes a novel fragile zero watermarking (FZW) method by fusing fragile watermarking and zero watermarking. The FZW method mainly includes two parts: (1) To guarantee high image quality, two least significant bits of pixel values of before-transmission and after-transmission images are extracted as image features, which are then embedded into the constructed binary original watermarking by XOR operation to generate the register watermarking and reconstructed watermarking; (2) To detect image attacks, the register watermarking and reconstructed watermarking are compared by bit-wise, and if they are same, it means that there is no attack, otherwise attacks occur. Real-time control experiments on networked inverted pendulum visual servo system platform confirm the feasibility and effectiveness of the proposed method.
Abstract Multi-stage attack is a kind of sophisticated intrusion strategy that has been widely us... more Abstract Multi-stage attack is a kind of sophisticated intrusion strategy that has been widely used for penetrating the well protected network infrastructures. To detect such attacks, state-of-the-art research advocates the use of hidden markov model (HMM). However, despite the HMM can model the relationships and dependencies among different alerts and stages for detection, they cannot handle well the stage dependencies buried in a longer sequence of alerts. In this paper, we tackle the challenge of the stages’ long-term dependency and propose a new detection solution using a sequence-to-sequence (seq2seq) model. The basic idea is to encode a sequence of alerts (i.e., detector’s observation) into a latent feature vector using a long-short term memory (LSTM) network and then decode this vector to a sequence of predicted attacking stages with another LSTM. By the encoder-decoder collaboration, we can decouple the local constraint between the observed alerts and the potential attacking stages, and thus able to take the full knowledge of all the alerts for the detection of stages in a sequence basis. By the LSTM, we can learn to “forget” irrelevant alerts and thereby have more opportunities to “remember” the long-term dependency between different stages for our sequence detection. To evaluate our model’s effectiveness, we have conducted extensive experiments using four public datasets, all of which include simulated or re-constructed samples of real-world multi-stage attacks in controlled testbeds. Our results have successfully confirmed the better detection performance of our model compared with the previous HMM solutions.
International Journal of Antennas and Propagation, 2017
A novel kind of compact dual-band quadrature patch coupler for vehicular beam-forming array is pr... more A novel kind of compact dual-band quadrature patch coupler for vehicular beam-forming array is proposed for the first time in this paper. To keep the performance of the first operating frequency 2.4 GHz (for Bluetooth Low Energy (BLE)) and generate the second operating frequency 5.9 GHz (for Dedicated Short Range Communications (DSRC)) simultaneously, complementary triangular split resonant rings (CTSRRs) and splitting gaps are employed to improve the performance of this new coupler; final size of the proposed coupler is 0.24λg (for 2.4 GHz). To validate the performance and design method of the coupler this paper proposed, a 3D model is constructed and optimized with ANSOFT HFSS firstly and then a coupler prototype is fabricated and measured. The measured results show that the amplitude unbalance (AU) is 0.54 dB and 0.44 dB for 2.4 GHz and 5.9 GHz, respectively, and the corresponding phase unbalance (PU) is 93.5 and 92 degrees, respectively.
Progress In Electromagnetics Research Letters, 2008
A novel planar omnidirectional array based on Quasi-Yagi antenna is proposed in this paper. The m... more A novel planar omnidirectional array based on Quasi-Yagi antenna is proposed in this paper. The modeling of this antenna and design method based on equivalent circuits have been developed. An eight-unit planar array has been designed, fabricated and measured. Measured results exhibit good performance of the return loss and radiation pattern in horizontal plane. The gain of the array in horizontal plane was about 0 dBi. The un-roundness of the radiation pattern in horizontal plane was about 5 dB.
Journal of Electromagnetic Waves and Applications, 2009
A compact low insertion loss vertical transition and power divider (PD) using millimeter wave cir... more A compact low insertion loss vertical transition and power divider (PD) using millimeter wave circuit/module is presented. Substrate integrated circular cavity (SICC) is employed to improve the performance of transition and PD structure. Two different D simulation tools are employed to validate the design method of the structure.
2007 International Conference on Communications, Circuits and Systems, 2007
An investigation of 94.5 GHz avalanche diode high order frequency multiplier is presented. The no... more An investigation of 94.5 GHz avalanche diode high order frequency multiplier is presented. The nonlinearity property of avalanche phenomenon has evoked great interest in high order frequency multiplication. Theoretical analysis of harmonic characters of avalanche current is outlined. In experiment 4.1 mW output power and 0.8% efficiency are obtained. Meanwhile the phase noise of 84 dBc/Hz at 10 KHz offset
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Papers by Dakui Wu