Bulletin of NTU "KhPI". Series: Problems of Electrical Machines and Apparatus Perfection. The Theory and Practice / Вісник Національного технічного університету "ХПІ". Серія: Проблеми удосконалювання електричних машин і апаратів. Теорія і практика
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A computational approach to the N-back task
No full textThe N -back task is one of the most popular paradigms for studying the
cognitive mechanisms of working memory (WM). The task requires the observer to view
a sequence of stimuli and judge whether the current stimulus (probe) matches the one
presented N stimuli ago (target). A key phenomenon is that the intervening stimuli (distractors) interfere with task performance. Unfortunately, the classic N -back task uses
complex categorical stimuli, making it unfit to quantify the effect of feature similarity on
interference strength. Here, we introduce the “analog N -back task", which utilizes stimuli varying continuously in orientation or color. This task variant enables us to measure
interference strength on a continuum, providing data suitable for identifying the sources
of interference using computational models. In the analog 2-back task, we found that
interference increased with feature similarity between the probe and both task-relevant
(1-back) and task-irrelevant (3-back) distractors. We next developed and evaluated three
main models that each incorporated a Bayesian decision step and differed from an optimal non-interference model in one component only: an early-pooling model, a late-pooling
model, and a substitution model. Model comparison suggests that interference emerges late in processing, most likely due to confusion between stimuli during WM retrieval. Our
work puts the study of interference in the N -back task on a firmer computational footing and provides a unified framework for examining the sources of interference across
domains
Нормалізація магнітного поля в житлових приміщеннях, розташованих над вбудованими трансформаторними підстанціями 6(10)/0,4 кВ потужністю 100-400 кВА
Get PDFThe purpose of the work is to define methods and means of screening, sufficient to reduce to a safe level the low frequency magnetic field in residential premises of old buildings, located above built-in transformer substations 6(10)/0,4 kV power 100–400 kVA at short distances to the premises. To achieve this goal, a modified method for synthesizing active shielding systems of the magnetic field for transformer substations at short distances from the substation to the floor of the premises, and its experimental verification was carried out on a full-scale physical model of a transformer substation power 100 kVA with a physical layout of the synthesized active shielding system. A synthesis of active shielding systems of magnetic field for transformer substations with a power of 100–400 kVA at short distances from the substation to the floor of the premises and an analysis of their effectiveness were carried out. It was determined that the normalization of the magnetic field on the floor surface for transformer substations with a power of 100 kVA using a synthesized active shielding system with one compensation winding is possible at distances of at least 1,15 m from the substation, and with two windings - at least 1,02 m. It was determined that normalization of the magnetic field on the floor surface for 400 kVA transformer substations using a synthesized active shielding system with two windings is possible only at a distance from the substation of at least 1,6 m. An analysis of the effectiveness of the combined use of active and passive shielding was conducted. It was determined that the combined use of synthesized two-channel active shielding systems and a passive flat electromagnetic shield made of 4 mm thick aluminum sheet allows reducing the magnetic field above the built-in transformer substation with a power of 100 to 400 kVA to the normative level while limiting the distance from the substation to the floor of the premises to at least 1,08 m and provides protection of public health from the effects of the low frequency magnetic field.Метою роботи є визначення методів та засобів екранування, достатніх для зменшення до безпечного рівня магнітного поля промислової частоти в житлових приміщеннях будинків старої забудови, розташованих над вбудованими трансформаторними підстанціями 6(10)/0,4 кВ потужністю 100–400 кВА при малих відстанях до приміщення. Для досягнення поставленої мети запропоновано модифікований метод синтезу систем активного екранування магнітного поля трансформаторних підстанцій при малих відстанях від підстанції до підлоги приміщення, та проведена його експериментальна перевірка на повномасштабному фізичному макеті трансформаторної підстанції потужності 100 кВА з фізичним макетом синтезованої системи активного екранування. Проведено синтез систем активного екранування магнітного поля трансформаторних підстанцій потужності 100–400 кВА при малих відстанях від підстанції до підлоги приміщення та аналіз їх ефективності. Визначено, що нормалізація магнітного поля на поверхні підлоги для трансформаторних підстанцій потужності 100 кВА з допомогою синтезованої системи активного екранування з однією компенсаційною обмоткою можлива на відстанях не менш 1,15 м від підстанції, а з двома обмотками - не менш 1,02 м. Визначено, що нормалізація магнітного поля на поверхні підлоги для трансформаторних підстанцій 400 кВА з допомогою синтезованої системи активного екранування з двома обмотками можлива тільки при відстані від підстанції не менш 1,6 м. Проведено аналіз ефективності комбінованого використання активного та пасивного екранування. Визначено, що комбіноване використання синтезованих двоканальних систем активного екранування та пасивного плоского електромагнітного екрану з алюмінієвого листа товщиною 4 мм дозволяє зменшити магнітне поле над вбудованою трансформаторною підстанцією потужністю від 100 до 400 кВА до нормативного рівня при обмеженні відстані від підстанції до підлоги приміщень не менш 1,08 м і забезпечує захист здоров’я населення від впливу магнітного поля промислової частоти
Дослідження кореляції між параметрами діелектричної абсорбції при обстеженні ізоляції трьохжильних силових кабелів із застосуванням сукупних вимірювань
Get PDFThree-core power cables with paper-impregnated insulation in a common metal sheath contain several layers of dielectric formed by phase and belt insulation between the cores and the sheath. When diagnosing the technical condition of the insulation of such cables according to the parameters of electrical capacity and tg δ, the problem of experimental determination of individual parameters for each of the insulation layers of the power cable arises. When evaluating the individual values of the dielectric absorption parameters of each of the insulating layers in three-wire power cables by applying aggregate measurements, the formation of a system of equations can be carried out in two different ways. In the first case, the unknown values of the capacitance and tg δ of each of the 6 insulating layers (of which 3 are formed by the insulation layers between the cores of the power cable and 3 dielectric layers between each of the cores and the sheath) are directly determined by solving a system of 6 linear algebraic equations. In the second case, the individual parameters of the dielectric are determined by minimizing the root-mean-square error of solving the redefined system of equations using the method of least squares. According to the results of the calculations, it is shown that when evaluating the uncertainties of dielectric absorption parameters using aggregate measurements, the correlations between the aggregate values can be disregarded.Стаття присвячена дослідженню кореляційних зв’язків між результатами вимірювань сукупних значень електричної ємності та тангенса кута діелектричних втрат ізоляції трьохжильних силових кабелів з паперовою імпрегнованою ізоляцією в спільній металевій оболонці. За результатами проведених розрахунків показано, що при оцінюванні невизначеностей вимірювань параметрів діелектричної абсорбції із застосуванням сукупних вимірювань кореляційні зв’язки між сукупними значеннями електричної ємності та тангенса кута діелектричних втрат можна не враховуват
An experimental manipulation of the value of effort
No full textPeople who take on challenges and persevere longer are more likely to succeed in life. But individuals often avoid exerting effort, and there is limited experimental research investigating whether we can learn to value effort. We developed a paradigm to test the hypothesis that people can learn to value effort and will seek effortful challenges if directly incentivized to do so. We also dissociate the effects of rewarding people for choosing effortful challenges and performing well. The results provide limited evidence that rewarding effort increased people’s willingness to choose harder tasks when rewards were no longer offered (near-transfer). There was also mixed evidence that rewarding effort increased willingness to choose harder tasks in another unrelated and unrewarded task (far-transfer). These heterogeneous results highlight the need for further research to understand when this paradigm may be the most effective for increasing and generalizing the value of effort
Occupational Portrait of A Pandemic Workforce: Latin Americans in the Health and the Sales & Services Sectors of Canada
No full textReflecting on present COVID-19 pandemic times in Canada and using both visible and ethnic ancestry information from the 2016 census, the author produced an occupational portrait of the Latin American workforce of the Health and Sales & Services sectors of the country. The focus was on full-time, full-year workers, aged 25-64, who received employment income in 2015. The workforce in the Health and Sales & Services sectors totaled 5.5 thousand and 24.3 thousand individuals respectively. The occupational portrait, which was developed based on the Canadian 2016 NOC occupational classification system, revealed an active participation of Latino workers in activities enhancing sanitary protection and the economic survival of the Canadian population. Women, and established and recent immigrants as well as those reporting Central American ethnic origins were found among those who most participated in the economic activities of the sectors. The most typical jobs performed by Latin American workers were as nursing aides in the Health sector and janitorial (males) and light or specialized cleaners (women) in the Sales & Services sector. The nature of these jobs made them a high health-risk group and vulnerable one in pandemic times as they entail working in close proximity to other colleagues and the general public
Using speed and accuracy and the Simon effect to explore the output form of inhibition of return
No full textInhibition of return (IOR) refers to slower responses to targets presented at previously cued locations. Contrasting target discrimination performance over various eye movement conditions has shown the level of activation of the reflexive oculomotor system determines the nature of the effect. Notably, an inhibitory effect of a cue nearer to the input end of the processing continuum is observed when the reflexive oculomotor system is actively suppressed, and an inhibitory effect nearer the output end of the processing continuum is observed when the reflexive oculomotor system is actively engaged. Furthermore, these two forms of IOR interact differently with the Simon effect. Drift diffusion modelling has suggested that two parameters can theoretically account for the speed-accuracy tradeoff rendered by the output-based form of IOR: increased threshold and decreased trial noise. In Experiment 1, we demonstrate that the threshold parameter best accounts for the output-based form of IOR by measuring it with intermixed discrimination and localization targets. Experiment 2 employed the response-signal methodology and showed that the output-based form has no effect on the accrual of information about the target's identity. These results converge with the response bias account for the output form of IOR
WTA, WTP, and the WTA/WTP disparity in Chinese Social Media Platforms: Descriptive Statistics and Associations with Personality and Social Media Use
No full textThe amount of money individuals were willing to accept (WTA) to discontinue using prominent Chinese social media platforms (WeChat/QQ), the willingness to pay (WTP) for using these platforms, as well as WTA/WTP disparities were investigated in between-groups and within-subjects design studies to examine their existence, size, and psychological correlates in the form of personality and social media use habits. Individuals were recruited at Chinese universities in three separate surveys. For between-groups investigations, four samples were extracted: WTA and WTP samples for investigations in the context of WeChat as well as WTA and WTP for QQ. For within-subjects investigations, individuals completed items on WTA and WTP for WeChat/QQ, the Big Five Inventory, time spent on WeChat/QQ, and the short Bergen Social Media Addiction Scale. Two samples providing data on WeChat and QQ, respectively, were extracted. Across study designs and for both WeChat and QQ we found evidence for high WTA and lower WTP scores, thus, large WTA/WTP disparities. Individual differences in the disparities were negatively associated with Openness across platforms. The results reveal a generally low acceptance to pay for social media use, which is important against the background of discussions on monetary payment models. Moreover, a complex interplay between individual characteristics, characteristics of the service, and how and why the service is used seem to underly WTA and the WTA/WTP disparity. Finally, methodological implications of the present results for forthcoming studies assessing valuation (WTA, WTP) in the context of social media are discussed
Personal Narratives Build Trust Across Ideological Divides
No full textLack of trust is a key barrier to collaboration in organizations and is exacerbated in contexts when employees subscribe to different ideological beliefs. Across five preregistered experiments, we find that people judge ideological opponents as more trustworthy when opposing opinions are expressed through a self-revealing personal narrative than through either data or stories about third parties---even when the content of the messages is carefully controlled to be consistent. Trust does not suffer when explanations grounded in self-revealing personal narratives are augmented with data, suggesting that our results are not driven by quantitative aversion. Perceptions of trustworthiness are mediated by the speaker's apparent vulnerability and are greater when the self-revelation is of a more sensitive nature. Consequently, people are more willing to collaborate with ideological opponents who support their views by embedding data in a self-revealing personal narrative, rather than relying on data-only explanations. We discuss the implications of these results for future research on trust as well as for organizational practice
The primacy of behavioral research for understanding the brain
No full textUnderstanding the brain requires us to answer both what the brain does, and how it does it. Using a series of examples, I make the case that behavior is often more useful than neuroscientific measurements for answering the first question. Moreover, I show that even for “how” questions that pertain to neural mechanism, a well-crafted behavioral paradigm can offer deeper insight and stronger constraints on computational and mechanistic models than do many highly challenging (and very expensive) neural studies. I conclude that behavioral, rather than neuroscientific research, is essential for understanding the brain, contrary to the opinion of prominent funding bodies and scientific journals, who erroneously place neural data on a pedestal and consider behavior to be subsidiary