A Survey on Supervised,Unsupervised,and Semi-Supervised Approaches in Crowd Counting

Quantifying the number of individuals in images or videos to estimate crowd density is a challenging yet crucial task with significant implications for fields such as urban planning and public safety.Crowd counting has attracted considerable attention in the field of computer vision,leading to the development of numerous advanced models and methodologies.These approaches vary in terms of supervision techniques,network architectures,and model complexity.Currently,most crowd counting methods rely on fully supervised learning,which has proven to be effective.However,this approach presents challenges in real-world scenarios,where labeled data and ground-truth annotations are often scarce.As a result,there is an increasing need to explore unsupervised and semi-supervised methods to effectively address crowd counting tasks in practical applications.This paper offers a comprehensive review of crowd counting models,with a particular focus on semi-supervised and unsupervised approaches based on their supervision paradigms.We summarize and critically analyze the key methods in these two categories,highlighting their strengths and limitations.Furthermore,we provide a comparative analysis of prominent crowd counting methods using widely adopted benchmark datasets.We believe that this survey will offer valuable insights and guide future advancements in crowd counting technology.

Tailoring the microstructure and mechanical properties of the final Al-Mn foils by different intermediate annealing process

In this work, two different intermediate annealing processes, single-step annealing（SSA, 530?C/15 h）and two-step annealing（TSA, 450?C/5 h + 530?C/15 h）, were used to tailor microstructure before coldrolling and annealing of the final twin-roll cast Al-Mn foils. The recrystallization behavior and mechanical properties during annealing of severely cold-rolled foils were systematically studied. Our results show that discontinuous recrystallization occurs in SSA-foils during annealing at 150–310?C, in contrast with continuous recrystallization in TSA-foils. The continuous recrystallization develops much finer grains（;.35 μm） in the TSA-foils than those by discontinuous recrystallization in the SSA-foils（;4.7 μm）. The texture components in cold-rolled TSA-foils hardly change（retained rolling-textures） after continuous recrystallization, while those in the cold-rolled SSA-foils mainly transform into a strong cube component{001} <100> after discontinuous recrystallization. Finally, a maximized elongation to fracture of;3.9%was achieved in the TSA-foil, much higher than that of the SSA-counterparts,;.3%. The relationships between the microstructure and mechanical properties were discussed.

The ecological system and the regionalization of landscape reconstruction in northwest of China

The northwest of China is a vast area with abundant resources and significant potential for development.However,the ecological system is extremely vulnerable to damage and must be managed carefully.Thus,the Chinese government is strengthening research on improvement and reconstruction of the ecological system and landscape in northwest of China while moving forward with large-scale development in west China.The disadvantages and vulnerabilities in the northwest area in China are presented.It is suggested that the reconstruction of landscape should be conducted by step by step regionalization across the various ecological systems in the 3.04 million km^(2) northwest area of China.The first level regionalization results of reconstruction of landscape are discussed.