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Optimal gear shift control of two-speed dual-clutch transmission in electric vehicle for smoothness and friction loss reduction
No full textAn optimal shift control strategy for electric vehicles with the two-speed dual-clutch transmission is proposed to reduce the vehicle jerk and friction work during gear shift. The dynamic model of the powertrain considering the stick–slip friction of clutch is built. The developed control scheme is divided into two stages. For the upper level control, a finite-time linear quadratic regulator (LQR) is designed to optimize the target trajectories of torque and speed of motor and clutch by integrating both jerk and friction work in the cost function. Considering that the clutch torque is necessary for calculating the target trajectories but cannot be measured directly, the Kalman filter is employed to estimate the clutch torque. For the lower level control, a combination of torque feedforward and speed feedback controller is constructed to control the motor torque and clutch pressure. To validate the effectiveness of the proposed strategy, comparisons with the strategies based on the polynomial method and unsmooth LQR are carried out. Simulation results and hardware-in-loop test reveal that the jerk and friction work are both reduced, indicating better shift performance
A different type of leadership style : Michael Jordan – a great void or a shooting star?
No full textResearch methodology
The data used to present this case was collected from secondary data sources. These sources included media reports associated with Michael Jordan and his trajectory since entering the sport, as well as specific information published about his time at the Chicago Bulls. Another key source of information is the ESPN documentary conducted specifically on Jordan’s relationship with his National Basketball Association (NBA) team.
Case overview/synopsis
The case follows the story of Michael Jordan, who took his team, the Chicago Bulls, to fame in a rather controversial manner. To do so, Michael Jordan had to alter his leadership style over the years to be respected as a leader and motivate his team to win one NBA championship after another. On 20th April 2020, ESPN’s “The Last Dance”, a 10-part documentary about Michael Jordan and his time playing for the Chicago Bulls was released to much acclaim. The documentary became highly noted as Jordan himself, both directed and starred in the documentary. Jordan’s great achievements stood out, but so did the conflicts that the basketball star had with The Bulls’ management team and mainly, his teammates. Relationships between teammates were far from harmonious, which led to questions around whether Michael Jordan was as good a leader, as he was a star player. Cultural change within the organisation was primarily linked to the often-contested leadership of Jordan.
Complexity academic level
The case can be used at UG, MSc and MBA levels. It works for in-person teaching and for online teaching. It is most suitable in leadership, strategy and strategy in practice courses. However, it is critical to note that the case can shed light on the dynamics that leaders and teammates have within their teams. Therefore, this case may be valuable to students studying courses where they themselves must work in groups and oftentimes encounter challenges in managing their team. These challenges can arise at all levels of experience. As such, the case provides particularly useful reflection for decision makers who may be beginning to develop their leadership skill (UG), those who have already experienced working in teams (MSc) or leading teams themselves (MBA, Executive MBA). The case addresses the challenges associated with achieving high team motivation and performance. It also sheds light on the challenges associated with leading a cultural change within a team and the approaches of different actors involved. It may be best to introduce the case in the context of a (1.5–2 h) workshop once students understand the basic frameworks and tools used to analyse leadership styles and their characteristics
Momentum particle maximum likelihood
No full textMaximum likelihood estimation (MLE) of latent variable models is often recast as the minimization of a free energy functional over an extended space of parameters and probability distributions. This perspective was recently combined with insights from optimal transport to obtain novel particle-based algorithms for fitting latent variable models to data. Drawing inspiration from prior works which interpret `momentum-enriched' optimization algorithms as discretizations of ordinary differential equations, we propose an analogous dynamical-systems-inspired approach to minimizing the free energy functional. The result is a dynamical system that blends elements of Nesterov's Accelerated Gradient method, the underdamped Langevin diffusion, and particle methods. Under suitable assumptions, we prove that the continuous-time system minimizes the functional. By discretizing the system, we obtain a practical algorithm for MLE in latent variable models. The algorithm outperforms existing particle methods in numerical experiments and compares favourably with other MLE algorithms
Practitioner Review : continuity of mental health care from childhood to adulthood for youths with ADHD : who, how and when?
No full textMany youths with attention-deficit/hyperactivity disorder (ADHD) experience significant long-term impairment and may develop concurrent mental and somatic health difficulties as adults. This is associated with burden and costs for the individual and society which could be prevented through continued support in youth. Yet, only few young people transition to adult mental health services for ongoing care in different countries worldwide. We provide an overview on current transition practices, highlighting the gaps in knowledge and the barriers to effective service transitioning, while considering the large geographical variation in available guidelines and service provision. For ease of use, this review is organized in a question-and-answer format covering different aspects of the transition process and considering both service users’ and clinicians’ perspectives. Consensus is needed to identify those that require continued care, the optimal timing to arrange transition, and the most suitable services. Finally, we discuss cost-effectiveness of transition practices, consider examples of best practice, and propose recommendations on how to improve transitional care, including the importance of service users’ input into transition planning
Wald tests when restrictions are locally singular
No full textWald-type tests are convenient because they allow one to test a wide array of linear and nonlinear restrictions from a single unrestricted estimator; we focus on the problem of implementing Wald-type tests for nonlinear restrictions. We provide examples showing that Wald statistics in non-regular cases can have several asymptotic distributions; the usual critical values based on a chi-square distribution can both lead to under-rejections and over-rejections; indeed, the Wald statistic may diverge under the null hypothesis. We study the asymptotic distribution of Wald-type statistics for the class of polynomial restrictions and show that the Wald statistic either has a non-degenerate asymptotic distribution, or diverges to infinity. We provide conditions for convergence and a general characterization of this distribution. We provide bounds on the asymptotic distribution (when it exists). In several cases of interest, this bound yields an easily available conservative critical value. We propose an adaptive consistent strategy for determining whether the asymptotic distribution exists and which form it takes
The impact of ring-shaped laser beam on dissimilar welding of Al-Cu thin sheets for battery tab-to-busbar connection : microstructural, mechanical and electrical characteristics
No full textAl-Cu dissimilar laser welding has gained substantial attention in the electric vehicle battery manufacturing, while challenged by the formation of brittle Al-Cu intermetallic compounds (IMCs). This study investigated the impact of beam shaping technology on the characteristics of Al-Cu dissimilar laser welds by using a coaxial core and ring dual beam laser system. The investigation assessed multi-level weld characteristics including weld geometry, IMC formation, mechanical and electrical properties. Results showed that the dual laser beam can effectively avoid imperfections observed with single beam, such as full penetration related to core-only beam and surface discontinuity defects associated with ring-only beam, respectively. For the core-only weld, extensive upward migration of Cu promoted the formation of brittle CuAl2 and Cu9Al4/Cu3Al2, leading to a considerable reduction in joint strength and a sharp increase in the electrical resistance. For the ring-only weld, the insufficient bonding area between Al and Cu sheet, leads to a significant degradation of joint strength, although a minimal electrical resistance was identified. An optimized power splitting was determined at 40% for the core beam and 60% for the ring beam, which allows the minimal formation of Al-Cu IMCs and consequently, the improved mechanical strength and reduced electrical resistance
Measurement of ambient radon progeny decay rates and energy spectra in liquid argon using the MicroBooNE detector
No full textIs it French? Popular postnational screen fiction from France
No full textThis book investigates the recently accelerated phenomenon of mainstream French film and serial television’s remarkable popularity not only within but – more novelly for European audiovisual narratives – outside the domestic context. Treating changes that have taken place in France's production landscape during the mass rollout of global streaming platforms as revelatory of broader tendencies in media production and circulation in Europe and beyond, the collection explores emergent influential players (Omar Sy, Camille Cottin, Alexandre Aja and Fanny Herrero), companies such as Netflix and Gaumont, and new genres, identities and representations on screen. It thus draws together a body of new research by international experts in French and European media production to analyse popular film and television series from France through a postnational lens with regards to both economic and institutional norms and to culture as a whole
