Enhancing Thermoelectric Performance in Single-Crystal-Like Semiconducting Films by Tuning the Carrier Scattering Mechanism

College of Engineering-Interdepartmenta

Safety Guaranteed Manipulation Based on Reinforcement Learning Planner and Model Predictive Control Actor

Deep reinforcement learning (RL) has been endowed with high expectations in tackling challenging manipulation tasks in an autonomous and self-directed fashion. Despite the significant strides made in the development of reinforcement learning, the practical deployment of this paradigm is hindered by at least two barriers, namely, the engineering of a reward function and ensuring the safety guaranty of learning-based controllers. In this paper, we address these challenging limitations by proposing a framework that merges a reinforcement learning \lstinline[columns=fixed]{planner} that is trained using sparse rewards with a model predictive controller (MPC) \lstinline[columns=fixed]{actor}, thereby offering a safe policy. On the one hand, the RL \lstinline[columns=fixed]{planner} learns from sparse rewards by selecting intermediate goals that are easy to achieve in the short term and promising to lead to target goals in the long term. On the other hand, the MPC \lstinline[columns=fixed]{actor} takes the suggested intermediate goals from the RL \lstinline[columns=fixed]{planner} as the input and predicts how the robot's action will enable it to reach that goal while avoiding any obstacles over a short period of time. We evaluated our method on four challenging manipulation tasks with dynamic obstacles and the results demonstrate that, by leveraging the complementary strengths of these two components, the agent can solve manipulation tasks in complex, dynamic environments safely with a $100\%$ success rate. Videos are available at \url{https://videoviewsite.wixsite.com/mpc-hgg}

Robust Fine Registration of Multisensor Remote Sensing Images Based on Enhanced Subpixel Phase Correlation

Automatic fine registration of multisensor images plays an essential role in many remote sensing applications. However, it is always a challenging task due to significant radiometric and textural differences. In this paper, an enhanced subpixel phase correlation method is proposed, which embeds phase congruency-based structural representation, L1-norm-based rank-one matrix approximation with adaptive masking, and stable robust model fitting into the conventional calculation framework in the frequency domain. The aim is to improve the accuracy and robustness of subpixel translation estimation in practical cases. In addition, template matching using the enhanced subpixel phase correlation is integrated to realize reliable fine registration, which is able to extract a sufficient number of well-distributed and high-accuracy tie points and reduce the local misalignment for coarsely coregistered multisensor remote sensing images. Experiments undertaken with images from different satellites and sensors were carried out in two parts: tie point matching and fine registration. The results of qualitative analysis and quantitative comparison with the state-of-the-art area-based and feature-based matching methods demonstrate the effectiveness and reliability of the proposed method for multisensor matching and registration.TU Berlin, Open-Access-Mittel – 202

Study of the Digestate as an Innovative and Low-Cost Adsorbent for the Removal of Dyes in Wastewater

Digestate, as an urban solid waste, was considered as an innovative adsorbent for colorant polluted wastewater. Batch adsorption experiments were carried out using digestate as an adsorbent material to remove various dyes belonging to different categories. The removal rate and adsorption capacity of dyes were evaluated and the dose of digestate, contact time, and initial dye concentration were studied. The maximum removal rate was approximately 96% for Methylene Blue. The equilibrium time for the Methylene Blue was 4 h, while for other dyes, a longer contact time was required to reach the equilibrium. The suspicion of colloidal matter release into the solution from solid fraction of the digestate led to the investigation of the consequence of a washing step of the digestate adsorbent upstream the adsorption experiment. Washed and not washed adsorbents were tested and the differences between them in terms of dye removal were compared. Moreover, experimental data were fitted by pseudo-first order, pseudo-second order, and intra-partial diffusion kinetic models as well as Langmuir, Freundlich, and Sips isotherm models. The results from fitted models showed that the adsorption of various dyes onto the digestate was mostly well fitted by the Langmuir isotherm and pseudo-second-order kinetic model

Towards a Global Schema for Web Entities

Popular entities often have thousands of instances on the Web. In this paper, we focus on the case where they are presented in table-like format, namely appearing with their attribute names. It is observed that, on one hand, for the same entity, different web pages often incorporate different attributes; on the other, for the same attribute, different web pages often use different attribute names (labels). Therefore, it is imaginably difficult to produce a global attribute schema for all the web entities of a given entity type based on their web instances, although the global attribute schema is usually highly desired in web entity instances integration and web object extraction. To this end, we propose a novel framework of automatically learning a global attribute schema for all web entities of one specific entity type. Under this framework, an iterative instances extraction procedure is first employed to extract sufficient web entity instances to discover enough attribute labels. Next, based on the labels, entity instances, and related web pages, a maximum entropy-based schema discovery approach is adopted to learn the global attribute schema for the target entity type. Experimental results on the Chinese Web achieve weighted average Fscores of 0.7122 and 0.7123 on two global attribute schemas for person-type and movie-type web entities, respectively. These results show that our framework is general, efficient and effective

Power Line Communication with Robust Timing and Carrier Recovery against Narrowband Interference for Smart Grid

Power line communication (PLC) is an important interconnection technology for the smart grid, but the robustness of PLC transmission is faced with a great challenge due to strong non-Gaussian noise and interference. In this paper, a narrowband interference (NBI) resistant preamble is designed, and an effective timing and frequency synchronization method is proposed for OFDM-based PLC systems in the smart grid, which is capable of simultaneously conveying some bits of transmission parameter signaling (TPS) as well. In the time domain, the cyclic extension of the training OFDM symbol is scrambled, which makes it feasible to combat against NBI contamination. More accurate timing detection and sharper correlation peak can be implemented under the power line channel and the AWGN channel in the presence of NBI, compared with the conventional Schmidl’s and Minn’s methods with the same preamble length. Furthermore, the TPS transmitted using the proposed method is also immune from the NBI. The proposed method is capable of improving the synchronization performance of the PLC transmission significantly, which is verified by theoretical analysis and computer simulations

High-Quality Development Path of the "Enclave Economy" from the Perspective of Symbiosis: A Case Study of Guangqing Economic Cooperation Zone (Guangde Park)

The "enclave economy" is an important governance tool for promoting regional integration. Guangdong Province occupies the leading position in exploring the "enclave economy" model in China, which has effectively promoted the development of the east and northwest of Guangdong Province through the "point to area" approach. However, certain problems that are associated with the "enclave economy" concept, including a weak level of industrial relatedness, disconnection with the development of the local urban system, and inadequate interest driving mechanisms, need to be urgently addressed. The article aims to explore the high-quality development path of the "enclave economy" in the new era, taking advantage of the symbiosis theory. Based on field research and semi-structured interview methods, the present study attempts to not only probe into the cooperative relationship and mutually beneficial symbiosis mechanism among different actors in the "enclave economy" but also explore a more sustainable and mutually beneficial development "enclave economy" model. With respect to theoretical contribution, based on the symbiosis theory and the characteristics of the "enclave economy", this study facilitates a better understanding of the high-quality development logic of the "enclave economy" from the perspective of symbiosis in particular and establishes a theoretical framework comprising the "industrial symbiosis network-industrial symbiosis unit-interest symbiosis mechanism" components. Empirically, this study takes the Guangqing Economic Cooperation Zone (Guangde Park) as the case study; reveals the development process and problems of the "enclave economy", including the isolation of industry transplantation, fragmentation of industry-city units, and locking of interests and mismatch between rights and responsibilities; and proposes high-quality development strategies, such as establishing a cross-regional "enclave economic circle", a resource-linking platform between industry and city, and a community of interests in industrial parks and towns, to form a more sustainable symmetric and mutually beneficial symbiotic mechanism. The key contribution of this study lies in the theoretical framework for the high-quality development of the "enclave economy" through the lens of symbiosis, which enriches the ways of analysis and cognitive logic of the "enclave economy" and advances cross-regional cooperation and "enclave economy" research. It enhances the cross-territorial geographic thinking of regional cooperation and "enclave economy" research, holding the potential to provide decision-making references for the promotion of regional coordinated development in Guangdong Province in the new period. It also has practical application value for relieving the pressure of unbalanced and insufficient regional development in China by promoting cross-municipal and cross-provincial cooperation