Under the environment of ocean development, underwater object detection technology has been widely used. Underwater salient object detection technology plays an important role in this process. The characteristics of light transmission under water determine the attenuation of color information in underwater images. In this paper, a method of underwater salient object detection based on red channel correction is designed based on the characteristics of the fastest attenuation of red channel in underwater images. First, the red channel component of the underwater image is weighted and corrected, and then the corrected three RGB components are used to construct the quaternion. The salient target detection calculation is carried out by PQFT method, and finally the salient object image is obtained. Experimental results show that, compared with the traditional SR and PQFT methods, the proposed method has higher accuracy and lower error rate in detecting the boundary of visually significant underwater object.
Summary This paper presents a solution to guarantee a fault‐tolerant control (FTC) of dynamic positioning (DP) vessel in the presence of the position reference system (PRS) faults by using the backstepping technique. The faults modes of PRS are modeled as an additive uncertainty in the feedback loop of the DP control system, and the bounds of the additive uncertainty are unknown. Through estimating online the unknown bounds on the basis of the designed adaptive mechanism, the robust adaptive fault‐tolerant controller (RAFTC), which takes the faulty PRS measurements as the inputs, is proposed rather than detecting and isolating them. Moreover, the developed RAFTC is proved by applying Lyapunov stability theory that the closed‐loop DP control system is uniformly bounded and the tracking error can be converged to zero asymptotically despite of the PRS failures. A simulation scenario on an offshore supply vessel model is provided to validate the effectiveness of the designed RAFTC, and the results show that the RAFTC has better performance and robustness compared with the ordinary fine‐tuned adaptive backstepping controller.
Objective This study was designed to evaluate the expression and its significance of colorectal carcinoma-associated antigen LEA in colorectal carcinoma cells through the comparison of a new monoclonal antibody (ND-1) and anti-CEA monoclonal antibody.Methods Expression of LEA and CEA in colorectal carcinoma cells was detected with immunocytochemistry and flow cytometry . The specificity of LEA and CEA in colorectal cancercells was analyzed by ELISA, and to detect the expression of LEA in colorectal cancer tissues with immunohistochemical method.Results Flow cytometry detection showed that positive peak mean fluorescence intensity was gradually decreasing in the expression of LEA in CCL-187,CX-1,CLoneA and CCL-229,and stronger than that of CEA(P0.01). LEA was highly expressed in the well differentiated colorectal cancer cells of CCL-187 and CX-1,and its expression amount in low invasive cell lines of CCL-187 and CX-1 was higher than high invasive ones of CLoneA and CCL-229(P0.01).ELISA analysis revealed that monoclonal antibody ND-1 had stronger specific binding activity to the colorectal carcinoma cell lines as compared to the CEA(P0.01).The expression of LEA was decreased following the drop of tumor differentiation degree(P0.01)and exhibited higher selectivity in well differentiated colorectal cancer(P0.01).CEA had similar selectivity in well, moderately,and poorly differentiated colorectal cancer(P0.05).Conclusion LEA is more specific well differentiation colorectal carcinoma-associated antigen. LEA may be related to the differentiation degree, invasiveness and malignancy degree of cancer cells. LEA can be used as a useful measurement for the early diagnosis and malignancy degree of colorectal carcinoma.
A compact and planar dual band antenna for Bluetooth and ultra-wideband (UWB) is presented. The antenna exhibits a dual band operation covering Bluetooth (2.4-2.484 GHz) and UWB (3.1-10.6 GHz) frequency bands. It is composed of a semi-circular and an L-shaped strip and fed by a microstrip line and built on a FR4 substrate with only 23 × 35 mm 2 surface area. Details of the antenna design and measured results are presented and discussed.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)