mmPlace: Robust Place Recognition with Intermediate Frequency Signal of Low-cost Single-chip Millimeter Wave Radar

Place recognition is crucial for tasks like loop-closure detection and re-localization. Single-chip millimeter wave radar (single-chip radar in short) emerges as a low-cost sensor option for place recognition, with the advantage of insensitivity to degraded visual environments. However, it encounters two challenges. Firstly, sparse point cloud from single-chip radar leads to poor performance when using current place recognition methods, which assume much denser data. Secondly, its performance significantly declines in scenarios involving rotational and lateral variations, due to limited overlap in its field of view (FOV). We propose mmPlace, a robust place recognition system to address these challenges. Specifically, mmPlace transforms intermediate frequency (IF) signal into range azimuth heatmap and employs a spatial encoder to extract features. Additionally, to improve the performance in scenarios involving rotational and lateral variations, mmPlace employs a rotating platform and concatenates heatmaps in a rotation cycle, effectively expanding the system's FOV. We evaluate mmPlace's performance on the milliSonic dataset, which is collected on the University of Science and Technology of China (USTC) campus, the city roads surrounding the campus, and an underground parking garage. The results demonstrate that mmPlace outperforms point cloud-based methods and achieves 87.37% recall@1 in scenarios involving rotational and lateral variations.Comment: 8 pages, 8 figure

A Two-Class Stochastic Network Equilibrium Model under Adverse Weather Conditions

Adverse weather condition is one of the inducements that lead to supply uncertainty of an urban transportation system, while travelers’ multiple route choice criteria are the nonignorable reason resulting in demand uncertainty. This paper proposes a novel stochastic traffic network equilibrium model considering impacts of adverse weather conditions on roadway capacity and route choice criteria of two-class mixed roadway travellers on demand modes, in which the two-class route choice criteria root in travelers’ different network information levels (NILs). The actual route travel time (ARTT) and perceived route travel time (PRTT) are considered as the route choice criteria of travelers with perfect information (TPI) and travelers with bounded information (TBI) under adverse weather conditions, respectively. We then formulate the user equilibrium (UE) traffic assignment model in a variational inequality problem and propose a solution algorithm. Numerical examples including a small triangle network and the Sioux Falls network are presented to testify the validity of the model and to clarify the inner mechanism of the two-class UE model under adverse weather conditions. Managerial implications and applications are also proposed based on our findings to improve the operation efficiency of urban roadway network under adverse weather conditions

Transformation and products of captopril with humic constituents during laccase-catalyzed oxidation: Role of reactive intermediates

The transformation of captopril (CAP), a widely-used thiol drug, was studied with the presence of dissolved model humic constituents (HCs) in a laccase-catalyzed system. Reaction products were analyzed by ultra-performance liquid chromatography coupled to time-of-flight mass spectrometry and condensed fukui function computation. CAP reacted with different model HCs in the enzymatic system for 1 h, ranging from 75% (syringic acid) to 96% (p-coumaric acid). In the absence of HCs, only 15% of CAP was removed through self-coupling. The presence of HCs apparently changed the transformation of CAP in aqueous environment, and the HC reactive intermediates played an important role. First, during laccase catalysis, HCs with different structures were oxidized to produce reactive intermediates, including phenoxyl radical cation, ortho-, and pars-quinone intermediates. Second, these intermediates were readily attacked by CAP via nucleophilic reactions, forming C-S-C covalent conjugates. More importantly, the standard reduction potential of these intermediates is a critical parameter, as PCA showed the highest reactivity to the nucleophilic addition reaction with CAP by forming phenoxy radical cations. While SYR showed the least reactivity due to the formation of pars-quinone intermediates. Therefore, the functional groups on HCs could greatly influence the cross-coupling with CAP, as well as the type and stability of the coupling products. This work clearly demonstrated the transformation of CAP and other thiol drugs with the presence of HCs in aqueous environment, which is similar to the natural humification process. (C) 2016 Elsevier Ltd. All rights reserved.</p

How to Maintain Sustainable Development of China’s Agriculture under the Restriction of Production Resources? Research with Respect to the Effect on Output of the Substitution of Input Factors

China agricultural development has been facing the problem of resource constraints because its resources per capita such as land and energy are relatively lower than the global average. By applying the provincial agricultural panel data from 2000 to 2015 and fixed effect model based on the translog production function, this paper estimates both output elasticities and substitution elasticities of agricultural inputs, which may provide insights into sustainable agricultural development. The results show that, except for capital, the output elasticities of other production factors are all positive. Energy has always played an important role in agricultural production, whose elasticity in agriculture increased from 0.0203 in 2000 to 0.1694 in 2015. We also find a severe scarcity of land, and the high intensity of energy in the field of agriculture. Moreover, there exists a substitute relationship between all factors, which means that in the short term, one production factor can be employed to replace another to maintain agricultural development. From the empirical results of this paper, some policy suggestions are proposed as follows: it is crucial that more attention should be placed on land and to plan energy use wisely. In addition, on account of the current situation in China, the input of labor force should be stepped up and energy should be used more efficiently to make up for the shortage of land resources. The empirical results and policy suggestions in this paper may benefit the sustainable development of China’s agricultural economy

How to Maintain Sustainable Development of China&rsquo;s Agriculture under the Restriction of Production Resources? Research with Respect to the Effect on Output of the Substitution of Input Factors

China agricultural development has been facing the problem of resource constraints because its resources per capita such as land and energy are relatively lower than the global average. By applying the provincial agricultural panel data from 2000 to 2015 and fixed effect model based on the translog production function, this paper estimates both output elasticities and substitution elasticities of agricultural inputs, which may provide insights into sustainable agricultural development. The results show that, except for capital, the output elasticities of other production factors are all positive. Energy has always played an important role in agricultural production, whose elasticity in agriculture increased from 0.0203 in 2000 to 0.1694 in 2015. We also find a severe scarcity of land, and the high intensity of energy in the field of agriculture. Moreover, there exists a substitute relationship between all factors, which means that in the short term, one production factor can be employed to replace another to maintain agricultural development. From the empirical results of this paper, some policy suggestions are proposed as follows: it is crucial that more attention should be placed on land and to plan energy use wisely. In addition, on account of the current situation in China, the input of labor force should be stepped up and energy should be used more efficiently to make up for the shortage of land resources. The empirical results and policy suggestions in this paper may benefit the sustainable development of China&rsquo;s agricultural economy

A Physics Based Analytical Model of Undoped Body MOSFETs

A continuous physics based analytic model of undoped (or lightly doped) body MOSFETs has been derived in this paper by incorporating the solution of the Poisson equation into Pao-Sah integrated current equation using SPP approach. The closed form solutions of band bending and the inversion charge as a function of gate voltage and channel voltage were first derived from the combination of Gauss's law with the Poisson equation. Then, a continuous non-charge-sheet-based analytical model is developed for the undoped body MOSFETs. © 2004 IEEE

Distinct synergetic effects in the ozone enhanced photocatalytic degradation of phenol and oxalic acid with Fe3+/TiO2 catalyst

In this work, phenol and oxalic acid (OA) degradation in an ozone and photocatalysis integrated process was intensively conducted with Fe-3+/TiO2 catalyst. The ferrioxalate complex formed between Fe3+ and oxalate accelerated the removal of OA in the ozonation, photolysis and photocatalytic ozonation process, for its high reactivity with ozone and UV. Phenol was degraded in ozonation and photolysis with limited TOC removal rates, but much higher TOC removal was achieved in photocatalytic ozonation due to the generation of -OH. The sequence of UV light and ozone in the sequential process also influences the TOC removal, and ozone is very powerful to oxidize intermediates catechol and hydroquinone to maleic acid. Fenton or photo-Fenton reactions only played a small part in Fe3+/TiO2 catalyzed processes, because Fe3+ was greatly reduced but not regenerated in many cases. The synergetic effect was found to be highly related with the property of the target pollutants. Fe3+/TiO2 catalyzed system showed the highest ability to destroy organics, but the TiO2 catalyzed system showed little higher synergy. (C) 2017 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.</p