Automatic Truss Design with Reinforcement Learning

Truss layout design, namely finding a lightweight truss layout satisfying all the physical constraints, is a fundamental problem in the building industry. Generating the optimal layout is a challenging combinatorial optimization problem, which can be extremely expensive to solve by exhaustive search. Directly applying end-to-end reinforcement learning (RL) methods to truss layout design is infeasible either, since only a tiny portion of the entire layout space is valid under the physical constraints, leading to particularly sparse rewards for RL training. In this paper, we develop AutoTruss, a two-stage framework to efficiently generate both lightweight and valid truss layouts. AutoTruss first adopts Monte Carlo tree search to discover a diverse collection of valid layouts. Then RL is applied to iteratively refine the valid solutions. We conduct experiments and ablation studies in popular truss layout design test cases in both 2D and 3D settings. AutoTruss outperforms the best-reported layouts by 25.1% in the most challenging 3D test cases, resulting in the first effective deep-RL-based approach in the truss layout design literature.Comment: IJCAI2023. The codes are available at https://github.com/StigLidu/AutoTrus

ULK1/2 Constitute a Bifurcate Node Controlling Glucose Metabolic Fluxes in Addition to Autophagy

揭示了在外界能量供应缺乏时，细胞通过激活ULK1来介导葡萄糖分解代谢重编程以维持胞内的能量与氧化还原稳态的详细机制，并创新地发现了ULK1独立于自噬的关键功能。基于自噬和糖代谢与人类健康的重要相关性，该研究将很可能为我们预防和治疗各类代谢疾病提供新的思路和药物靶点。Metabolic reprogramming is fundamental to biological homeostasis, enabling cells to adjust metabolic routes after sensing altered availability of fuels and growth factors. ULK1 and ULK2 represent key integrators that relay metabolic stress signals to the autophagy machinery. Here, we demonstrate that, during deprivation of amino acid and growth factors, ULK1/2 directly phosphorylate key glycolytic enzymes including hexokinase (HK), phosphofructokinase 1 (PFK1), enolase 1 (ENO1), and the gluconeogenic enzyme fructose-1,6-bisphosphatase (FBP1). Phosphorylation of these enzymes leads to enhanced HK activity to sustain glucose uptake but reduced activity of FBP1 to block the gluconeogenic route and reduced activity of PFK1 and ENO1 to moderate drop of glucose-6-phosphate and to repartition more carbon flux to pentose phosphate pathway (PPP), maintaining cellular energy and redox homeostasis at cellular and organismal levels. These results identify ULK1/2 as a bifurcate-signaling node that sustains glucose metabolic fluxes besides initiation of autophagy in response to nutritional deprivation.State Key Program of National Natural Science of China， the 973 Program；National Natural Science Foundation of China for Fostering Talents in Basic Research ；the Foundation for Innovative Research Groups of the National Natural Science Foundation of China； and the 111 Project of Education of China

Roadmap on photonic metasurfaces

Funding: C.R. and U.L. acknowledge support through the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy via the Excellence Cluster 3D Matter Made to Order (EXC-2082/1, Grant No. 390761711). A.B.E. acknowledges support through the Cluster of Excellence PhoenixD (EXC 2122, Project ID No. 390833453). I.F.-C. and C.R. acknowledge support through the CRC Waves: Analysis and Numerics (SFB 1173, Grant No. 258734477. K.A. acknowledges funding from the Swiss National Science Foundation (Project No. PZ00P2_193221).Here we present a roadmap on Photonic metasurfaces. This document consists of a number of perspective articles on different applications, challenge areas or technologies underlying photonic metasurfaces. Each perspective will introduce the topic, present a state of the art as well as give an insight into the future direction of the subfield.Peer reviewe

The mystery of zombie enterprises – “stiff but deathless”

Drawing on social exchange theory, this study uses data on China’s Shanghai and Shenzhen A-share listed companies from 2009 to 2016 to examine why zombie enterprises are “stiff but deathless.” We find that these enterprises are able to “linger breathlessly” due to government support in the form of increased subsidies and bank loans. The government is more inclined to grant subsidies to zombie companies that assume greater policy burdens, specifically those offering more jobs. Furthermore, an enterprise’s property rights do not influence the level of “blood transfusions” received, and government assistance fails to bolster operating efficiency or value. This phenomenon is further explored in the context of the incentives local government officials have to maintain employment stability. Our conclusions highlight the necessity and urgency of cleaning up zombie enterprises

Political connection, ownership structure, and corporate philanthropy in China : a strategic-political perspective

This paper investigates whether philanthropic giving decisions and amount of charitable giving are related to firms’ political connections and ownership type. To this end, Chinese firms listed on either the Shenzhen or Shanghai stock exchange between 2004 and 2011 are examined, where government interference in the business sector is prevalent, state ownership structure is dominant, and corporate political connections prevail. Our analyses show (1) a significant and positive relationship between political connections and the likelihood and extent of firm contributions; (2) a significant and negative relationship between state ownership and extent of firm contributions; and (3) a stronger relationship between political connections and corporate philanthropy in non-state-owned firms. These findings with regard to the relationship between corporate giving, political connections, and ownership type have important implications for understanding corporate giving behavior in China and in emerging markets in general

Principal-principal conflicts and corporate philanthropy : evidence from Chinese private firms

The principal–principal perspective suggests that controlling shareholders have excessive influence on corporate philanthropy and may direct corporate funds to charitable causes to support their personal interests. Analysis of a sample of Chinese private firms listed on the Shenzhen or Shanghai stock exchange between 2004 and 2011 shows that (1) there is a significant and negative relationship between corporate giving and the share held by the largest shareholders, suggesting that controlling shareholders are opportunistic in directing corporate charitable contributions; (2) there is a significant and positive relationship between corporate giving and the political connections of the largest shareholders and their agents, suggesting compatibility between corporate contributions and the personal interests of the controlling shareholders; (3) there is a stronger negative relationship between corporate giving and the share of the company held by the largest shareholders in politically connected firms, suggesting that political connections contribute to increased opportunistic corporate giving. Overall, our study provides important evidence for the 'one dominant controlling shareholder' phenomenon (yigududa) by testing and extending the principal–principal framework and showing that the largest shareholders of Chinese firms appear to donate to charitable causes that ultimately serve their personal interests at the expense of minority shareholders

The provincial border, information costs, and stock price crash risk

ABSTRACTBased on externalities in the allocation of interprovincial resources, we examine how geographic location affects firms’ access to resources and thus their information disclosure and stock price crash risk. The results show that border firms have a higher stock price crash risk than non-border firms. Mechanism tests find that border firms have lower available credit, higher financing costs, smaller fiscal subsidies, higher accrual earnings management, lower accounting conservatism, and a more positive tone in the management discussion and analysis section of the annual report. This indicates that resource shortages and aggressive information disclosure are important drivers of their higher stock price crash risk. Additional tests find no border effect in the borders of integrated areas or borders of areas adjacent to municipalities. Accelerating the digital transformation of the government and the information infrastructure construction, and strengthening external governance can partially alleviate the stock price crash risk of border firms

Corporate social responsibility and financial performance : the roles of government intervention and market competition

Incorporating instrumental and political views of corporate social responsibility (CSR), this study examines the relationship between CSR and corporate financial performance in China's unique institutional context, which is featured by the coexistence of a strong government and a transitional market economy. Our results show that (a) CSR positively affects financial performance, (b) state ownership weakens the relationship between CSR and financial performance, and (c) industry competition strengthens the relationship between CSR and financial performance for both state-owned and non-state-owned firms. This study reveals that, although both an instrumental view and a political view of CSR are applicable in China, the motivation to create economic benefits for firms dominates, and market competition increases the strategic use of CSR