The Euler characteristic of a generic wave front in a 3‐manifold

We give a relation between Euler characteristics of a generic closed Legendrian surface and its wavefront

The Euler number of a topologically stable singular surface in a 3‐manifold

A formula for the Euler number of a generic singular surface in a 3-manifold is given. This formula not only unifies the previous results but also allows some new applications

The Intermediate Polar PQ Gem - Status of WET Observations of 1996

A summary of the results on PQ Gem based on WET observations conducted in February 1996 is presented. The 13.9 min spin period of the white dwarf in the system and the orbital side-band at 14.5 min have been detected unambiguously. Searches for other periods in the system gave negative results

On the calculation of normals in free-surface flow problems

The use of boundary-conforming finite element methods is considered for the solution of surface-tension-dominated free-surface flow problems in three dimensions. This class of method is based upon the use of a moving mesh whose velocity is driven by the motion of the free surface, which is in turn determined via a kinematic boundary condition for the normal velocity. The significance of the method used to compute the normal direction at the finite element node points for a C0 piecewise-polynomial free surface is investigated. In particular, it is demonstrated that the concept of mass-consistent normals on an isoparametric quadratic tetrahedral mesh is flawed. In this case an alternative, purely geometric, normal is shown to lead to a far more robust numerical algorithm

X-ray variability of GRS 1915+105 during the low-hard state observed with the Indian X-ray astronomy experiment (IXAE)

The galactic superluminal transient X-ray source GRS 1915+105 was observed with the pointed proportional counters (PPCs) onboard the Indian satellite IRS-P3 during 1996 July 23-27. We report here details of the behavior of this source during the relatively quiet and low luminosity state. Large intensity variations by a factor of 2 to 3, generally seen in black-hole candidates, are observed at a time scale of 100 ms to few seconds. No significant variation is detected over larger time scale of minute or more. The intensity variations are described as sum of shots in the light curve, and the number distribution of the shots are found to be exponential function of the fluence and duration of the shots. The cross correlation spectrum between 6-18 keV and 2-6 keV X-rays is found to have asymmetry signifying a delay of the hard X-rays by about 0.2 to 0.4 sec. This supports the idea of hard X-rays being generated by Compton up-scattering from high energy clouds near the source of soft X-rays. Very strong and narrow quasi periodic oscillations in the frequency range 0.62 to 0.82 Hz are observed. We discuss about a model which explains a gradual change in the QPO frequencies with corresponding changes in the mass accretion rate of the disk.Comment: 14 pages including 6 figures. To appear in Astronomy and Astrophysics Supplement Serie

Search for optical bursts from the gamma ray burst source GBS 0526-66

Attempts were made to detect optical bursts from the gamma-ray burst source GBS 0526-66 during Dec. 31, 1984 to Jan. 2, 1985 and Feb. 23 to Feb. 24, 1985, using the one meter reflector of the Kavalur Observatory. Jan. 1, 1985 coincided with the zero phase of the predicted 164 day period of burst activity from the source (Rothschild and Lingenfelter, 1984). A new optical burst photon counting system with adjustable trigger threshold was used in parallel with a high speed photometer for the observations. The best time resolution was 1 ms and maximum count rate capability was 255,000 counts s(-1). Details of the instrumentation and observational results are presented

Modified variable neighborhood search algorithm for maximum power point tracking in PV systems under partial shading conditions

Photovoltaic (PV) systems are being increasingly popular for power generation from solar radiation as the usage of renewable energy grows. To improve the efficiency, the system should operate at its the maximum power point. Hence, several algorithms have been developed for this purpose. Continuous tracking for the maximum power point often leads to heavy energy loss. Furthermore, partial shading can dramatically lower the performance of the system. A modified variable neighborhood search algorithm is proposed resulting zero oscillations around the operating point. A set of variables are used to improve the system’s configurability in various atmospheric and geographical conditions. Simulation result proves the operation of the proposed algorithm, its accuracy, and its fast response time

A 15-Gbps BiCMOS XNOR gate for fast recognition of COVID-19 in binarized neural networks

The COVID-19 pandemic is spreading around the world causing more than 177 million cases and over 3.8 million deaths according to the European Centre for Disease Prevention and Control. The virus has devastating effects on economies, health, and well-being of worldwide population. Due to the high increase in daily cases, the available number of COVID-19 test kits in under-developed countries is scarce. Hence, it is vital to implement an effective screening method of patients using chest radiography since the equipment already exists. With the presence of automatic detection systems, any abnormalities in chest radiography that characterizes COVID-19 can be identified. Several artificial-intelligence algorithms have been proposed to detect the virus. However, neural networks training is considered to be time-consuming. Since computations in training neural networks are spent on floating-point multiplications, high computational power is required. Multipliers consume the most space and power among all arithmetic operators in deep neural networks. This paper proposes a 15 Gbps high-speed bipolar-complementary-metal-oxide-semiconductor (BiCMOS) exclusive-nor (XNOR) gate to replace multipliers in binarized neural networks. The proposed gate can be implemented on BiCMOS-based field-programmable gate arrays (FPGAs). This will significantly improve the response time in identifying chest abnormalities in CT scans and X-rays

Revolutionizing 3D Animation & 3D Modeling Education: A Comprehensive Study on the Impact of Blended Learning

The educational environment has undergone a significant transformation due to the widespread impact of the COVID-19 pandemic. Prompting creative solutions to issues in teaching and learning. This study explores the integration of blended learning, focusing on 3D animation and modeling education. Blended learning, which combines conventional and online approaches, is emerging as an effective method for increasing student engagement and performance. The research delves into the complexities of 3D animation and modeling courses, emphasizing the importance of creative thinking and mastery of animation principles. The study showcases the effectiveness of blended learning through improved student outcomes, emphasizing adaptability, and interactive learning. This research provides valuable insights for educators, highlighting the significance of flexible teaching methodologies and the integration of technology in shaping the future of 3D animation and 3D modeling education