4 research outputs found
Design and Development of Microcontroller System, Embedded Circuits and Applications
No full textNot availabl
Measurement of Σ+ transverse polarization in e + e − collisions at s = 3.68 − 3.71 GeV
No full textAbstract Using e + e − collision data collected with the BESIII detector at seven energy points ranging from 3.68 to 3.71 GeV and corresponding to an integrated luminosity of 652.1 pb −1, we present an energy-dependent measurement of the transverse polarization, relative phase and modulus ratio of the electromagnetic form factors of the Σ+ hyperon in the e + e − → Σ + Σ ¯ − reaction. At each energy point, no evident polarization is observed. These results are helpful to understand the production mechanism of the Σ+- Σ ¯ − pairs
Search for a dark baryon in the Ξ−→π−+invisible decay
No full textA search for a dark baryon is performed for the first time in the two-body decay Ξ−→π−+invisible using (10.087 ± 0.044) × 109 J / ψ events collected at a center-of-mass energy of s=3.097GeV with the BESIII detector at the BEPCII collider. No significant signal is observed, and the 90% (95%) confidence level upper limits on the branching fraction B(Ξ−→π−+invisible) are determined to be 4.2×10−5 (5.2×10−5), 6.9×10−5 (8.4×10−5), 6.5×10−4 (7.6×10−4), 1.1×10−4 (1.3×10−4) and 4.5×10−5 (5.5×10−5), under the dark baryon mass hypotheses of 1.07 GeV/ c 2, 1.10 GeV/ c 2, mΛ (1.116 GeV/ c 2), 1.13 GeV/ c 2, and 1.16 GeV/ c 2, respectively. The constraints obtained on the Wilson coefficients Cus,sL and Cus,sR are more stringent than the previous limits derived from the LHC searches for the colored mediators.LPHE-L
Feature-based object tracking in maritime scenes.
No full textA monitoring of presence, location and activity of various objects on the sea is essential for maritime navigation and collision avoidance. Mariners normally rely on two complementary methods of the monitoring: radar and satellite-based aids and human observation. Though radar aids are relatively accurate at long distances, their capability of detecting small, unmanned or non-metallic craft that generally do not reflect radar waves sufficiently enough, is limited. The mariners, therefore, rely in such cases on visual observations. The visual observation is often facilitated by using cameras overlooking the sea that can also provide intensified infra-red images. These systems or nevertheless merely enhance the image and the burden of the tedious and error-prone monitoring task still rests with the operator. This thesis addresses the drawbacks of both methods by presenting a
framework consisting of a set of machine vision algorithms that facilitate the monitoring tasks in maritime environment. The framework detects and tracks objects in a sequence of images captured by a camera mounted either on a board of a vessel or on a static platform over-looking the sea. The detection of objects is independent of their appearance and conditions such as weather and time of the day. The output of the framework consists of locations and motions of all detected objects with respect to a fixed
point in the scene. All values are estimated in real-world units, i. e. location is expressed in metres and velocity in knots. The consistency of the estimates is maintained by compensating for spurious effects such as vibration of the
camera. In addition, the framework continuously checks for predefined events such as collision threats or area intrusions, raising an alarm when any such event
occurs. The development and evaluation of the framework is based on sequences captured under conditions corresponding to a designated application. The independence of the detection and tracking on the appearance of the sceneand
objects is confirmed by a final cross-validation of the framework on previously unused sequences. Potential applications of the framework in various areas of maritime environment including navigation, security, surveillance and others are outlined. Limitations to the presented framework are identified and possible solutions suggested. The thesis concludes with suggestions to further directions of the research presented
