Development of Broadband Resistive–Capacitive Parallel–Connection Voltage Divider for Transient Voltage Monitoring

The on-site measurement of transient voltages is of great significance in analyzing the fault cause of power systems and optimizing the insulation coordination of power equipment. Conventional voltage transformers normally have a narrow bandwidth and are unable to accurately measure various transient voltages in power systems. In this paper, a wideband parallel resistive–capacitive voltage divider is developed, which can be used for online monitoring of transient voltages in a 220 kV power grid. The structures of the high-voltage and low-voltage arms were designed. The internal electric field distribution of the high-voltage arm was analyzed. The influence factors and improvement techniques of the upper frequency limit were studied. The parameters of the elements of the divider were determined. The voltage withstand performances and scale factors under lightning impulses and AC and DC voltages, the temperature stabilities of scale factors and the step response and bandwidth of the developed voltage divider were tested. The results show that the deviations of the scale factors under various voltage waveforms and different temperatures ranging from −20 to 40 °C are within 3%. The withstand voltage meets the relevant requirements specified in IEC60071-1-2011. The step response 10~90% rise time is approximately 29 ns, and the 3 dB bandwidth covers the range of DC to 10 MHz.

Face recognition in Service robotics: Analysis of the padding effect according to people age / Reconhecimento facial em robótica de serviço: análise do efeito de preenchimento de acordo com a idade das pessoas

Service robots usually perform repetitive tasks such as collecting garbage, cleaning the house, among others. This kind of robot needs different skills to perform its daily tasks, being people´s recognition a critical skill. One of the techniques used to improve face recognition is padding. The padding technique increases, by a given scale factor, the bounding box of a detected face. In previous work, we had presented a comparative analysis of the influence of the padding in the algorithm used for face recognition. This paper extends the previous analysis by considering the effect of various padding scale factors among different life stages (i.e., toddler, children, teenager, adult, senior, and golden oldie). The result of this analysis shows that increasing the bounding box of detected faces is less efficient for middle-aged people than for younger and elderly people.

Interannual Abundance Fluctuations of Two Oceanic Squids in the Pacific Ocean Can Be Evaluated Through Their Habitat Temperature Variabilities

Neon flying squid (Ommastrephes bartramii) and jumbo flying squid (Dosidicus gigas) are two commercially essential oceanic squids in the Pacific Ocean. An in-depth understanding of the mechanisms of their annual and interannual abundance fluctuations under environmental and climate variabilities can ensure ration and suitable management. Thus, the annual and interannual abundance fluctuations of the stock of the western winter-spring cohort of O. bartramii and D. gigas off Peru Exclusive Economic Zone (PEEZ) waters and their association with habitat temperature variabilities are explored in this study based on the historical Chinese Squid-jigging fishery data from 2003 to 2020. The habitat temperature variabilities were defined as the effective principal components of the SST at the squids’ two important habitats (spawning and feeding ground) through life histories according to the principal component analysis. The Hodrick—Prescott filter analysis was conducted to quantify the annual and interannual fluctuations of abundance and habitat temperature variabilities. Furthermore, the generalized additive model (GAM) was employed to investigate their associations. The results demonstrated different but not synchronous trends of abundance for O. bartramii and D. gigas. Regarding O. bartramii, the interannual abundance first decreased (2003∼2013) and then increased (after 2014). For D. gigas, the interannual abundance kept decreasing within 2003∼2020. Their annual trends have presented large fluctuations over years. The results of GAM indicated that using habitat temperature variabilities only can trace the abundance trend of O. bartramii and D. gigas at an interannual but not annual scale. Further studies verified that Pacific Decadal Oscillation (PDO) is a crucial factor affecting the interannual abundance trend of these two squids through the habitat temperature variabilities. However, this study indicates that the habitat temperature variabilities not only are related to other large-scale factors, which are not investigated currently at an interannual scale, but also, are combined with other small- or middle-scale factors at an annual scale on their impacts to the abundance fluctuations of these two squids. Therefore, in order to better explain the mechanisms of annual and interannual abundance fluctuations of O. bartramii and D. gigas under environmental and climate variabilities, the importance of combining other potential factors into consideration is highlighted.

On the Problem of Testing a Portable Acceleration Recorder under Orbital Flight Conditions.

The paper discusses the possibility of testing and correcting calibration of a portable acceleration recorder under orbital flight conditions. This recorder in-cludes a 3-axis accelerometer. The most difficult stage of calibration tests is the determination of its scale factors. The main difficulty of calibration is the lack of special equipment on the space station. It is proposed to use a standard mass meter installed on the ISS for testing accelerometers. The algorithms considered in the paper use data of the motion of the mass meter platform and the video camera records processing in addition to the recorder readings. For testing the algorithms under earth conditions, recordings were made that simulate conditions of an orbital flight. The proposed algorithms showed 2 % error in determining the scale factors of the accelerometers.

Observational Spatial Memory in North Island Robins (Petroica Longpies)

<p>Observational spatial memory is employed by members of food-hoarding species to pilfer caches created by other individuals more effectively. North Island robins (Petroica australis) experience high levels of reciprocal cache pilferage within mate pairs. These circumstances were hypothesised to produce conditions under which advanced pilferage strategies such as observational spatial memory may evolve. Here I tested the ability of North Island robins to use observational spatial memory to discriminate between varying prey rewards. Three experiments were conducted which differed in the maximum number of prey items offered as a reward. Additional variables of retention interval, number of cache sites and a variable reward were included to assess how the birds’ memory was affected by small-scale factors. Results showed that North Island robins performed above chance expectations in most treatment combinations, indicating that they were able to utilize observational spatial memory. They were equally able to discriminate between different combinations of prey numbers that were hidden in 2, 3 and 4 caches sites from between 0, 10 and 60 seconds. Overall results indicate that North Island robins can solve complex numerical problems involving more than two parameters and up to one minute long retention intervals without training.</p>

Observational Spatial Memory in North Island Robins (Petroica Longpies)

<p>Observational spatial memory is employed by members of food-hoarding species to pilfer caches created by other individuals more effectively. North Island robins (Petroica australis) experience high levels of reciprocal cache pilferage within mate pairs. These circumstances were hypothesised to produce conditions under which advanced pilferage strategies such as observational spatial memory may evolve. Here I tested the ability of North Island robins to use observational spatial memory to discriminate between varying prey rewards. Three experiments were conducted which differed in the maximum number of prey items offered as a reward. Additional variables of retention interval, number of cache sites and a variable reward were included to assess how the birds’ memory was affected by small-scale factors. Results showed that North Island robins performed above chance expectations in most treatment combinations, indicating that they were able to utilize observational spatial memory. They were equally able to discriminate between different combinations of prey numbers that were hidden in 2, 3 and 4 caches sites from between 0, 10 and 60 seconds. Overall results indicate that North Island robins can solve complex numerical problems involving more than two parameters and up to one minute long retention intervals without training.</p>

Local Linear Scale Factors in Map Projections of an Ellipsoid

The main problem in cartography is that it is not possible to map/project/transform a spherical or ellipsoidal surface into a plane without distortions. The distortions of areas, angles, and/or distances are immanent to all maps. It is known that scale changes from point to point, and at certain points, the scale usually depends on the direction. The local linear scale factor c is one of the most important indicators of distortion distribution in the theory of map projections. It is not possible to find out the values of the local linear scale factor c in directions of coordinate axes x and y immediately from the definition of c. To solve this problem, in this paper, we derive new formulae for the calculation of c for a rotational ellipsoid. In addition, we derive the formula for computing c in any direction defined by dx and dy. We also considered the position and magnitude of the extreme values of c and derived new formulae for a rotational ellipsoid.