Backward Conditioning Research Articles

Deep learning for Mean Field Games with non-separable Hamiltonians

This paper introduces a new method based on Deep Galerkin Methods (DGMs) for solving high-dimensional stochastic Mean Field Games (MFGs). We achieve this by using two neural networks to approximate the unknown solutions of the MFG system and forward–backward conditions. Our method is efficient, even with a small number of iterations, and is capable of handling up to 300 dimensions with a single layer, which makes it faster than other approaches. In contrast, methods based on Generative Adversarial Networks (GANs) cannot solve MFGs with non-separable Hamiltonians. We demonstrate the effectiveness of our approach by applying it to a traffic flow problem, which was previously solved using the Newton iteration method only in the deterministic case. We compare the results of our method to analytical solutions and previous approaches, showing its efficiency. We also prove the convergence of our neural network approximation with a single hidden layer using the universal approximation theorem.

A Review of Backward Higher-Order Conditioning: Implications for a Pavlovian Conditioning Analysis of Stimulus Equivalence.

Stimulus equivalence (SE) is demonstrated when participants exposed to conditional discrimination training pass tests for reflexivity, symmetry, transitivity, and equivalence (symmetry combined with transitivity). Most theorists attribute the origin of SE to operant processes, but some argue that it results from Pavlovian conditioning. Symmetry is problematic for the latter hypothesis because it seems to require excitatory backward conditioning. However, equivalence tests resemble backward sensory preconditioning (BSP) and backward second-order conditioning (BSOC), two well-established processes. A review of associationistic theories of BSP and BSOC showed that the temporal coding hypothesis (TCH) explains outcomes that other associationistic theories cannot explain (i.e., BSOC and BSP effects after first-order conditioning with delay vs. trace conditioning and forward vs. backward conditioning). The TCH assumes that organisms encode the temporal attributes of stimulus events (e.g., order and interval duration) and this temporal information is integrated across separate phases of training. The TCH seems compatible with a behavioral analysis if direct stimulus control replaces the notion of temporal maps. The TCH perspective does not seem applicable to SE because SE tests are not predictive tasks. This suggests that SE is fundamentally different from BSP and BSOC and a Pavlovian conditioning analysis of SE is inadequate. This conclusion is consistent with previous criticism of a Pavlovian account of SE according to which Pavlovian conditioning cannot be interpreted as stimulus substitution.

Adversarial ink: componentwise backward error attacks on deep learning

Abstract Deep neural networks are capable of state-of-the-art performance in many classification tasks. However, they are known to be vulnerable to adversarial attacks—small perturbations to the input that lead to a change in classification. We address this issue from the perspective of backward error and condition number, concepts that have proved useful in numerical analysis. To do this, we build on the work of Beuzeville, T., Boudier, P., Buttari, A., Gratton, S., Mary, T. and Pralet S. (2021) Adversarial attacks via backward error analysis. hal-03296180, version 3. In particular, we develop a new class of attack algorithms that use componentwise relative perturbations. Such attacks are highly relevant in the case of handwritten documents or printed texts where, for example, the classification of signatures, postcodes, dates or numerical quantities may be altered by changing only the ink consistency and not the background. This makes the perturbed images look natural to the naked eye. Such ‘adversarial ink’ attacks therefore reveal a weakness that can have a serious impact on safety and security. We illustrate the new attacks on real data and contrast them with existing algorithms. We also study the use of a componentwise condition number to quantify vulnerability.

Study on the Dilemma of Implementing Rural LTC Insurance and the Implementation Path

Against the backdrop of China's ageing situation and the rising number of disabled persons, the Ministry of Human Resources and Social Security started to promote the construction of long-term care insurance in 2016. Compared to the mature LTC insurance models in developed Western countries, there are still many problems in the process of promoting LTC insurance in China due to the short duration of the pilot. This paper presents a synthesis of the dilemmas observed by different scholars in the process of promoting LTC insurance, and summarises the solutions and concrete implementation paths proposed by other scholars in response to these dilemmas. It can be found through the study that the lack of policies and laws, backward physical conditions and the difficulty in changing attitudes are the main reasons why it is difficult to promote LTC insurance in rural areas. Different scholars have accordingly put forward suggestions such as extending funding channels, strengthening the training of talents and creating a perfect care model.

Theoretical line loss calculation method for low-voltage distribution network via matrix completion and ReliefF-CNN

Line loss is directly responsible for the management profitability of the grid company. The traditional method of calculating the theoretical line loss for Low Voltage Distribution Networks (LVDN) necessitates more electrical parameters. which cannot be obtained easily. Besides, due to the backward communication conditions of LVDN, the problem of smart meter data missing is significant, which poses a challenge to an exact theoretical line loss calculation. In an attempt to solve the issues above, a theoretical line loss computation approach via matrix completion and ReliefF-convolutional neural network (CNN) for LVDN is proposed. Firstly, a feature weighting algorithm based on ReliefF is presented to analyze the relevance of the electrical parameters, which can be obtained easily. Secondly, a theoretical line loss calculation method is proposed for CNN-based. In the view of the data missing problem, a matrix completion method based on singular value thresholding (SVT) is introduced to obtain the high-precision data, in order to enhance the calculation accuracy of the theoretical line loss calculation. Finally, the proposed method is tested on the data sample of 789 LVDNs. The results show that comparing with CNN, back-propagation and other methods, the mean absolute percentage error (MAPE) of the presented method can reduce by more than 90%. When data missing, the MAPE of the proposed method can reduce by more than 95% compared with the method without considering the data completion.

The Role of Phonological Priming in Backward Priming Effects of Chinese Four-Character Words

The backward priming effect is found in the masked lexical decision tasks deploying Chinese four-character words as targets and the backward-presented words as primes. To explore whether phonology plays a role in this backward priming effect, we conducted two experiments using the masked priming lexical decision tasks. Thirty-two and sixty-three native Chinese speakers participated in the two experiments. Experiment 1 was designed to investigate the phonological priming in backward conditions and to ensure the exclusion of phonology in Experiment 1, the primes were presented forward in Experiment 2. The results showed that no significant phonological priming effect was found whether the primes were backward-presented or forward-presented. Therefore, it can be concluded that phonological priming did not contribute to the backward priming effect in lexical decision tasks.

Specificity of visual event-related potentials to subthreshold presentation of erotic pictures in pedophilia

To study visual event-related potentials (ERPs) associated with presentation of erotic pictures in backward masking condition in order to investigate perception, attention and information processing underlying the initiation and maintenance of abnormal sexual behavior in pedophilia. Participants (58 males committed sexual offenses against children) were divided into the pedophilia group (n=38) and the control group without disorders of sexual preference (n=20). Three types of stimuli were used: neutral pictures of nature (S1), adult heterosexual erotic pictures (S2) and erotic pictures with children (S3). Posterior N1 (N140) and anterior N1 (N120) and P3 (P320) ERP components were included in analysis. In both groups, the perception of erotic stimuli was accompanied by a significant increase in the amplitude and prolongation of the latency of the N140 and P320 components (p<0.001). N140 changes were characterized by right-hemispheric bias in both groups, however, asymmetry was observed for amplitude in the control group, and for latency - in the pedophilia group; besides, reactivity to S3 stimuli was weaker than to S2 ones in the pedophilia group. N120 amplitude was elevated significantly in response to S2 stimuli in the control group, and no changes were found in the pedophilia group. Between-group differences were revealed for early negative components N140 and N120, which parameters were entered as predictors into classification model based on discriminant analysis. The obtained accuracy of model was 87.23%. The specificity of neurophysiological reactions to erotic pictures in pedophilic patients corroborates the concept of disease as general neurodevelopmental disorder.

Degenerate Representation and Racism in Heart of Darkness

This paper has analyzed Joseph Conrad’s Heart of Darkness from Orientalist perspective. The term “Orientalism” has been a critical tool after Edward Said described how understanding of Europe about the non-Europeans became a weapon of maintaining power over the latter. This research has applied analytical and interpretivist approaches in discussion. The objective is to pinpoint why and how colonial rulers in the novel stereotypically produce representations of the Orient (here African is included) and create a false illusion that the West is “self” and the East is “other”. The selected text is analyzed in light of Edward Said’ description of the stereotypes of Oriental land and race as strange, inferior and wild. The search shows that Conrad presents Africans as uncivilized people, living in backward condition. He derogatorily describes them in their physical appearance and social behavior. Congo land is presented as wild, uncommon and mysterious. Europeans in the novel express their obsession that they are intelligent, skilled and much superior to the native and try to justify the colonial rule as an effort to civilize the African race and develop the place.

Shaykh Ja’far Mahmud Adam (d. 2007) and His Visions and Philosophical Thoughts on Education: An Inductive Approach

Education– no one doubts – essentially represents a strong instrument that is used in the process of executing revivalist projects, but also ensuring a development and advancement of people both at individual and societal level. That is why reformers pay great attention to knowledge which they, more than arguably, any other constituency of people, regard as the most potent weapon that facilitates the success of reform missions. The basic and common belief is that people find themselves in whatever deplorable condition and state of backwardness owing to their neglect of knowledge, which then makes them trapped in the shackles of ignorance. As a result, stressing the value of education and demonstrating this through operational initiatives by way of sensitizing, reawakening, enlightening and orienting people via various methods and approaches commensurate with the existing realities are all considered as steps toward liberating people from the grip of ignorance which has enslaved them until they rise and decisively fight it. This article highlights and appraises the educational views, thoughts and philosophy of Shaykh Ja’far Mahmud Adam (d. 2007), one of Nigeria’s most prominent Muslim reformers and most influential scholars. The article relies chiefly on the recorded speeches of the scholar in which he articulated his views during public occasions such as weekly Friday sermons, mosque lessons, public lectures or private study circles, which then circulated among larger Muslim audience. The essay finds out that Ja’far’s views on knowledge permeate both religious and Western education which he felt that society must standardize before it develops.

Single-ended limiting inductor voltage-ratio-derivative protection scheme for VSC-HVDC grids

Single-ended protection systems present the characteristics needed to fulfil the restrictive speed requirement related to high voltage direct current grids. This paper proposes a novel single-ended protection algorithm based on the DC voltage across the limiting inductors placed at each link end. Voltage measurements are taken at both terminals of the limiting inductors. The ratio between the link- and bus-side voltages enables fault discrimination between forward and backward fault conditions while providing directionality. Moreover, the derivative of the voltage-ratio is calculated in order to enable fast fault detection. The combined operation of these two algorithms avoids nuisance operations against fluctuations and close-up external faults. A trip signal is only issued to the circuit breakers when the individual criteria of both algorithms are simultaneously fulfilled. According to this, a protection scheme is developed, which covers link primary and backup as well as busbar protections. The performance of the proposed protection scheme is evaluated through simulations in a four-terminal grid. The selective, sensitive and accurate performance of the proposed protection scheme is demonstrated against faults up to 250 Ω while employing only local measurements, common limiting inductor sizes and a relatively low sampling frequency. Thus, the proposed protection scheme overcomes the sensitivity limitations related to high-resistance fault detection presented in derivative-based algorithms. Its proper operation under noise disturbances is also demonstrated.

Memory Modulation by Exercise in Young Adults Is Related to Lactate and Not Affected by Sex or BDNF Polymorphism.

Simple SummaryThe health and cognitive benefits associated with physical exercise are widely acknowledged. However, exercise characteristics responsible for the improvement in cognition, along with the underlying mechanisms, remain to be elucidated. In an attempt to resolve these questions, our study compares cognitive outcomes after two distinct exercise modes in young adults. Specifically, we have examined the differences between high-intensity interval exercise (HIIE) and moderate-intensity continuous exercise (MIE) on visuospatial and declarative memory, contemplating the influence of exercise-associated parameters such as released lactate and non-modifiable factors, including BDNF polymorphism and biological sex. Our results demonstrate the relevance of exercise intensity and intensity-dependent lactate release in modulating cognitive improvement following exercise with no association with the non-modifiable factors mentioned above. These data suggest that the exercise characteristics and intensity of exercise sessions should be carefully considered to optimize cognitive response in young adults. Conversely, the consideration of genotype and biological sex is inappreciable.Currently, high-intensity interval exercise (HIIE) is on the rise compared to moderate-intensity exercise (MIE) due to its similar benefits for health and performance with low time requirements. Recent studies show how physical exercise can also influence cognitive function, although the optimal dose and underlying mechanisms remain unknown. Therefore, in our study, we have compared the effects on visuospatial and declarative memory of different exercise intensities (HIIE vs. MIE), including possible implicated factors such as lactate released after each session and the Brain-Derived Neurotrophic Factor (BDNF) genotype. Thirty-six undergraduate students participated in this study. The HIIE session consisted of a 3 min warm-up, four 2 min sets at 90–95% of the maximal aerobic speed (MAS) with 2 min of passive recovery between sets, and a 3 min cooldown, and the MIE session implies the same total duration of continuous exercise at 60% of the MAS. Better improvements were found after HIIE than MIE on the backward condition of the visuospatial memory test (p = 0.014, ηp2 = 0.17) and the 48 h retention of the declarative memory test (p = 0.04; d = 0.34). No differences were observed in the forward condition of the visuospatial memory test and the 7-day retention of the declarative memory test (p > 0.05). Moreover, non-modifiable parameters such as biological sex and BDNF polymorphism (Val/Val, Val/Met, or Met/Met) did not modulate the cognitive response to exercise. Curiously, the correlational analysis showed associations (p < 0.05) between changes in memory (visuospatial and declarative) and lactate release. In this sense, our results suggest an important role for intensity in improving cognitive function with exercise, regardless of genetic factors such as biological sex or BDNF Val66Met polymorphism.

Executivo Central e Seleção de Alvos na Memória de Trabalho Visual

Abstract The goal of this study was to investigate if the selection of external information for storage in visual working memory requires control by the central executive when the categorization of targets is guided by instructions. The design was experimental 3 (concurrent task) x 2 (instruction). Forty-eight university students saw eight colored shapes, four of them surrounded by square outlines. Memory was assessed using a recognition task. Targets varied with instructions: targets were presented within squares in the first block and outside squares in the second block. There were three concurrent tasks: no task, articulatory suppression, and backward counting. Performance was measured by hits, false alarms, corrected recognition, and sensitivity (A’), compared using within-subject ANOVAs. Results showed a main effect only for concurrent task, with lower performance in the backward counting condition for all measures. These results suggest that the central executive does not control the perceptual filter, corroborating earlier results.

Mental imagery of whole-body motion along the sagittal-anteroposterior axis

Whole-body motor imagery is conceptualised as a mental symbolisation directly and indirectly associated with neural oscillations similar to whole-body motor execution. Motor and somatosensory activity, including vestibular activity, is a typical corticocortical substrate of body motion. Yet, it is not clear how this neural substrate is organised when participants are instructed to imagine moving their body forward or backward along the sagittal-anteroposterior axis. It is the aim of the current study to identify the fingerprint of the neural substrate by recording the cortical activity of 39 participants via a 32 electroencephalography (EEG) device. The participants were instructed to imagine moving their body forward or backward from a first-person perspective. Principal Component Analysis (i.e. PCA) applied to the neural activity of whole-body motor imagery revealed neural interconnections mirroring between forward and backward conditions: beta pre-motor and motor oscillations in the left and right hemisphere overshadowed beta parietal oscillations in forward condition, and beta parietal oscillations in the left and right hemisphere overshadowed beta pre-motor and motor oscillations in backward condition. Although functional significance needs to be discerned, beta pre-motor, motor and somatosensory oscillations might represent specific settings within the corticocortical network and provide meaningful information regarding the neural dynamics of continuous whole-body motion. It was concluded that the evoked multimodal fronto-parietal neural activity would correspond to the neural activity that could be expected if the participants were physically enacting movement of the whole-body in sagittal-anteroposterior plane as they would in their everyday environment.

Receiver Sand Mitigation Measures along railways: CWE-based conceptual design and preliminary performance assessment

Desert railways are constantly exposed to incoming wind-blown sand. The railway structure locally disturbs the incoming sand drift, induces its accumulation, and ultimately suffers its harmful effects. Receiver Sand Mitigation Measures (SMMs) aerodynamically interact with the track system, induce sand erosion around it, and allow sand transport far downwind it. The conceptual and preliminary design of an innovative Receiver SMM called Sand Blower is developed in this study. The design is grounded on the aerodynamic behaviour of the baseline humped sleeper track system. The flow control strategy is intended to avoid boundary layer separation, and to promote local flow acceleration by means of the Venturi effect. The performance assessment is carried out by Computational Wind Engineering approach. It allows to simulate the local wind flow, to obtain the shear stress field at the wall, and to derive from it sand sedimentation, windward erosion and backward erosion conditions. The results show that the Sand Blower greatly increases the track system performance by reducing sand sedimentation and increasing sand erosion under wide range of wind speeds and directions.

Negative correlation between word-level surprisal and intersubject neural synchronization during narrative listening

Word-predictability measures, such as surprisal, have been used to show that linguistic prediction is an essential neural mechanism for successful comprehension. However, the neural dynamic of this mechanism may differ across individuals listening to the same narrative, revealing possible idiosyncrasies. Therefore, in this study, we investigated the ability of the surprisal measure to address the linguistic prediction in terms of the intersubject phase synchronization (ISPS) among healthy volunteers listening to a narrative during continuous functional Magnetic Resonance Imaging (fMRI) scanning.The data of twenty-seven participants, acquired in a previous study, were re-analyzed to estimate the ISPS associated with an audiobook listening, played forward and backward. Mean ISPS differences between playing conditions were first analyzed across the whole brain. ISPS time-series during the forward condition was explained with both a lexical-only and a semantics-weighted lexical surprisal model of the narrative word series to detect correlations between ISPS and word surprisal values.Compared to the backward condition, mean ISPS was significantly higher during forward condition in a broad network encompassing frontal, temporal, and parietal areas. The lexical-only model disclosed significant negative ISPS-surprisal correlations in the angular gyrus bilaterally, precuneus, left inferior parietal lobule, left middle frontal gyrus, left cerebellum, and left inferior frontal gyrus. The semantics-weighted surprisal model disclosed significant negative ISPS-surprisal correlations in the right angular gyrus, right precuneus, and left inferior frontal gyrus.Besides engaging language-related areas, narrative processing induces significant ISPS levels beyond the language network. The negative ISPS-surprisal correlations observed would signal divergent neural dynamics among individuals, leading to lower group synchronization, when the words to be integrated are characterized by higher surprisal levels. These results provide further support to the use of language models, such as the surprisal, to explain the neural processes of narrative comprehension and additional information into how the human brain exploits predictions during language comprehension.

Impaired Categorical Perception of Speech Sounds Under the Backward Masking Condition in Adults Who Stutter.

Evidence increasingly indicates that people with developmental stuttering have auditory perception deficits. Our previous research has indicated similar but slower performance in categorical perception of the speech sounds under the quiet condition in children who stutter and adults who stutter (AWS) compared with their typically fluent counterparts. We hypothesized that the quiet condition may not be sufficiently sensitive to reveal subtle perceptual deficiencies in people who stutter. This study examined this hypothesis by testing the categorical perception of speech and nonspeech sounds under backward masking condition (i.e., a noise was presented immediately after the target stimuli). Fifteen Cantonese-speaking AWS and 15 adults who do not stutter (AWNS) were tested on the categorical perception of four stimulus continua, namely, consonant varying in voice onset time (VOT), vowel, lexical tone, and nonspeech, under the backward masking condition using identification and discrimination tasks. AWS demonstrated a broader boundary width than AWNS in the identification task. AWS also exhibited a worse performance than AWNS in the discrimination of between-category stimuli but a comparable performance in the discrimination of within-category stimuli, indicating reduced sensitivity to sounds that belonged to different phonemic categories among AWS. Moreover, AWS showed similar patterns of impaired categorical perception across the four stimulus types, although the boundary location on the VOT continuum occurred at an earlier point in AWS than in AWNS. The findings provide robust evidence that AWS exhibit impaired categorical perception of speech and nonspeech sounds under the backward masking condition. Temporal processing (i.e., VOT manipulation), frequency/spectral/formant processing (i.e., lexical tone or vowel manipulations), and nonlinguistic pitch processing were all found to be impaired in AWS. Altogether, the findings support the hypothesis that AWS might be less efficient in accessing the phonemic representations when exposed to a demanding listening condition. https://doi.org/10.23641/asha.20249718.

When do people learn likes and dislikes from co-occurrences? A dual-force perspective on evaluative conditioning

Evaluative Conditioning (EC) research shows that people learn their likes and dislikes due to the co-occurrence of stimuli (CS and US) in the environment. Most recent EC research addressed processes underlying this phenomenon: how do people acquire their likes and dislikes? We address the question of when people learn from co-occurrences. To understand when learning occurs rather than how it occurs, we apply a dual-force perspective (Bless & Fiedler, 2006). We propose that the environment provides a bottom-up force, for example, via spatial and temporal closeness of CS and US. The organism provides a top-down force, for example, by active inferences or existing knowledge about CS and US. We propose that these forces jointly determine when people learn from co-occurrences. We tested this dual-force perspective by creating experimental conditions that should lead to EC effects from both associative and propositional EC process models but should prevent EC effects from a dual-force perspective. Across four pre-registered laboratory experiments (N = 568) and two pre-registered online experiments (N = 440), we found that changing the top-down force weakened and eliminated (Experiments 1–3) or reinstated EC effects (Experiment 4), using a backward (Experiments 1–4) or forward conditioning procedure (Experiment 5–6), while keeping the environmental bottom-up force constant (Experiment 6). Independent of the how question (e.g., associative or propositional), these results support the dual-force perspective as a framework to predict when people learn their likes and dislikes from the co-occurrence of CS and US in the environment.

RESEARCH ON THE INNOVATION OF TEACHING MODE OF “FRESHMAN SEMINAR” IN APPLIED UNIVERSITIES UNDER THE CONCEPT OF OBE BASED ON THE CHANGE OF EMOTIONAL BEHAVIOR -- TAKING PHYSICAL EDUCATION MAJOR OF NANCHANG NORMAL UNIVERSITY AS AN EXAMPLE

Abstract Background “Freshman seminar”, as the first important learning revolution course for freshmen, originated in American colleges and universities in the middle of last century. It was not until 2003 that some research universities in China gradually launched the “freshman seminar”, which has become one of the most popular courses for the group. The course was set up late in application-oriented undergraduate colleges, and the overall teaching staff, teaching content, teaching mode and teaching evaluation are still immature and still in the exploratory stage. In particular, the emotional changes of students are not clear enough. Research design Taking the “freshman seminar” of physical education major in Nanchang Normal University as an example, this paper investigates the current situation and confusion of physical education teachers and students in Nanchang Normal University in 2019, 2020 and 2021 by means of questionnaire and interview. A total of 268 valid questionnaires were obtained. There were 6 questionnaires for teachers and 262 questionnaires for students. In order to study the impact of emotional regulation on female employees' retirement decision-making, the study adopts the Core Self-evaluation Scale. The core self-evaluation is measured by the core sel evaluation scale (CSES) compiled by judge et al. The scale consists of 10 items and adopts Likert 5-point scoring method. 1 ~ 5 points represent “very inconsistent” to “very consistent”. Previous studies have shown that the scale has good cross-cultural applicability. The internal consistency of the Core Self-evaluation Scale in this study α The coefficient is 0.824. 1.2.3 the emotional regulation self-efficacy scale adopts the emotional regulation self-efficacy scale (REEs) compiled by Caprara. Domestic research shows that the scale has high reliability and validity and is suitable for Chinese people. The scale adopts lik ⁃ ERT 5-point scoring and includes three dimensions: adjusting positive emotional efficacy, adjusting depression / pain emotional efficacy and adjusting anger / anger emotional efficacy. Emotion regulation self-efficacy scale Research results The teaching form of the freshman seminar in the Department of physical education of Nanchang Normal University is still based on the traditional theoretical lectures of administrative courses, and there is a lack of effective teaching means and methods to guide students to actively discuss. Another factor leading to the poor effect of classroom discussion is the lack of communication between teachers and students before class and students' ignorance of learning objectives. Single evaluation methods and relatively backward teaching conditions also make students lack learning motivation. Research Conclusion Based on the national undergraduate curriculum construction standards, this paper creatively puts forward the “group progressive interaction” teaching mode of “freshman seminar“ by combining the OBE education concept with the effective education theory, and constructs a curriculum teaching system with the unity of temperature, height, breadth and effectiveness. “Freshman seminar” is a teaching system with temperature, height, breadth and effectiveness. It can not only effectively improve the teaching quality of the course, but also provide some references for the “freshman seminar” of different majors in the same university. We should fully understand the important position of group discussion in group emotional factors and actively improve the group's role psychological ability. We should pay special attention to its impact on life attitude and healthy behavior, and be a healthy self-manager, coordinator and collaborator. According to the psychological characteristics of these groups, we should actively and flexibly organize colorful activities, strive to create a relaxed and harmonious living atmosphere, create a friendly and mutually beneficial emotional artificial intelligence relationship, encourage and guide these groups, adjust their psychology to the best state, and promote the healthy development of their good cognition and life. Acknowledgements One of the research results of the teaching reform research project of Nanchang Normal University, “Research on the Course Mode Innovation of Applied University Undergraduate Seminar Based on OBE Theory”, project number JGKT-19-02.

Energy loss mechanisms of transition from pump mode to turbine mode of an axial-flow pump under bidirectional conditions

Pump-as-turbine stations with ultra-low head often face the deterioration risk during load rejection operations when the demands in water delivery and power generation are satisfied. In the course of load rejection, significant energy transfer and hydraulic instability may ensue from the pump-to-turbine transition mode, and vice versa. In order to investigate the variation of energy loss during the transition process of a bidirectional axial-flow pump, the entropy production method is herein utilized for visualization and quantitative analysis of high energy loss regions within key components. In the process of transient simulation, the torque balance equation is applied for calculating the rotational speed of impeller. Two-way transitions are considered with the bidirectional pump for comparing two distinct forms of pumps equipped with front and rear guide vanes. Results show that the simulated external characteristic curves and transition parameters of the pump are in good accordance with the experimental data. The transient process of the transition successively goes through four modes, i.e. pump, braking, turbine and runaway modes. In the process of the direction switch of the main flow and rotation, the different positions of guide vanes also deeply influence the inflow angle and flow pattern in impeller, and then change the distribution of the pressure coefficient, vorticity and entropy production rate. In pump mode, the entropy production rate and pressure coefficient at the impeller inlet edge under backward transition condition (BTC) is higher than that under forward transition condition (FTC), due to the smaller inflow angle caused by the front guide vanes under BTC. In runaway operation, the total entropy production (TEP) under FTC is obviously higher than that under BTC, because the energy loss is reduced by the broken shedding vortices caused by the obstruction of the guide vanes under BTC. This study's results can be referred to while seeking for the operation safety and stability of the pump stations consecutively used to pump and generate power.

Dopamine errors drive excitatory and inhibitory components of backward conditioning in an outcome-specific manner

For over two decades, phasic activity in midbrain dopamine neurons was considered synonymous with the prediction error in temporal-difference reinforcement learning.1-4 Central to this proposal is the notion that reward-predictive stimuli become endowed with the scalar value of predicted rewards. When these cues are subsequently encountered, their predictive value is compared to the value of the actual reward received, allowing for the calculation of prediction errors.5,6 Phasic firing of dopamine neurons was proposed to reflect this computation,1,2 facilitating the backpropagation of value from the predicted reward to the reward-predictive stimulus, thus reducing future prediction errors. There are two critical assumptions of this proposal: (1) that dopamine errors can only facilitate learning about scalar value and not more complex features of predicted rewards, and (2) that the dopamine signal can only be involved in anticipatory cue-reward learning in which cues or actions precede rewards. Recent work7-15 has challenged the first assumption, demonstrating that phasic dopamine signals across species are involved in learning about more complex features of the predicted outcomes, in a manner that transcends this value computation. Here, we tested the validity of the second assumption. Specifically, we examined whether phasic midbrain dopamine activity would be necessary for backward conditioning-when a neutral cue reliably follows a rewarding outcome.16-20 Using a specific Pavlovian-to-instrumental transfer (PIT) procedure,21-23 we show rats learn both excitatory and inhibitory components of a backward association, and that this association entails knowledge of the specific identity of the reward and cue. We demonstrate that brief optogenetic inhibition of VTADA neurons timed to the transition between the reward and cue reduces both of these components of backward conditioning. These findings suggest VTADA neurons are capable of facilitating associations between contiguously occurring events, regardless of the content of those events. We conclude that these data may be in line with suggestions that the VTADA error acts as a universal teaching signal. This may provide insight into why dopamine function has been implicated in myriad psychological disorders that are characterized by very distinct reinforcement-learning deficits.