WP - liu hua

An installation commenting on the tragic death of a Chinese student studying at Wimbledon College of Arts and the historical relationship between China and Europe, referencing Orientalism, Chinoiserie and the Willow Pattern design

Divide and Fuse: A Re-ranking Approach for Person Re-identification

As re-ranking is a necessary procedure to boost person re-identification (re-ID) performance on large-scale datasets, the diversity of feature becomes crucial to person reID for its importance both on designing pedestrian descriptions and re-ranking based on feature fusion. However, in many circumstances, only one type of pedestrian feature is available. In this paper, we propose a "Divide and use" re-ranking framework for person re-ID. It exploits the diversity from different parts of a high-dimensional feature vector for fusion-based re-ranking, while no other features are accessible. Specifically, given an image, the extracted feature is divided into sub-features. Then the contextual information of each sub-feature is iteratively encoded into a new feature. Finally, the new features from the same image are fused into one vector for re-ranking. Experimental results on two person re-ID benchmarks demonstrate the effectiveness of the proposed framework. Especially, our method outperforms the state-of-the-art on the Market-1501 dataset.Comment: Accepted by BMVC201

Highly Efficient Regression for Scalable Person Re-Identification

Existing person re-identification models are poor for scaling up to large data required in real-world applications due to: (1) Complexity: They employ complex models for optimal performance resulting in high computational cost for training at a large scale; (2) Inadaptability: Once trained, they are unsuitable for incremental update to incorporate any new data available. This work proposes a truly scalable solution to re-id by addressing both problems. Specifically, a Highly Efficient Regression (HER) model is formulated by embedding the Fisher's criterion to a ridge regression model for very fast re-id model learning with scalable memory/storage usage. Importantly, this new HER model supports faster than real-time incremental model updates therefore making real-time active learning feasible in re-id with human-in-the-loop. Extensive experiments show that such a simple and fast model not only outperforms notably the state-of-the-art re-id methods, but also is more scalable to large data with additional benefits to active learning for reducing human labelling effort in re-id deployment

Timescales of carbon turnover in soils with mixed crystalline mineralogies

Organic matter–mineral associations stabilize much of the carbon (C) stored globally in soils. Metastable short-range-order (SRO) minerals such as allophane and ferrihydrite provide one mechanism for long-term stabilization of organic matter in young soil. However, in soils with few SRO minerals and a predominance of crystalline aluminosilicate or Fe (and Al) oxyhydroxide, C turnover should be governed by chemisorption with those minerals. Here, we correlate mineral composition from soils containing small amounts of SRO minerals with mean turnover time (TT) of C estimated from radiocarbon (¹⁴C) in bulk soil, free light fraction and mineral-associated organic matter. We varied the mineral amount and composition by sampling ancient soils formed on different lithologies in arid to subhumid climates in Kruger National Park (KNP), South Africa. Mineral contents in bulk soils were assessed using chemical extractions to quantify Fe oxyhydroxides and SRO minerals. Because of our interest in the role of silicate clay mineralogy, particularly smectite (2 : 1) and kaolinite (1 : 1), we separately quantified the mineralogy of the clay-sized fraction using X-ray diffraction (XRD) and measured ¹⁴C on the same fraction. <br><br> Density separation demonstrated that mineral associated C accounted for 40–70 % of bulk soil organic C in A and B1 horizons for granite, nephelinite and arid-zone gabbro soils, and &gt; 80 % in other soils. Organic matter strongly associated with the isolated clay-sized fraction represented only 9–47 % of the bulk soil C. The mean TT of C strongly associated with the clay-sized fraction increased with the amount of smectite (2 : 1 clays); in samples with &gt; 40 % smectite it averaged 1020 ± 460 years. The C not strongly associated with clay-sized minerals, including a combination of low-density C, the C associated with minerals of sizes between 2 µm and 2 cm (including Fe oxyhydroxides as coatings), and C removed from clay-sized material by 2 % hydrogen peroxide had TTs averaging 190 ± 190 years in surface horizons. Summed over the bulk soil profile, we found that smectite content correlated with the mean TT of bulk soil C across varied lithologies. The SRO mineral content in KNP soils was generally very low, except for the soils developed on gabbros under more humid climate that also had very high Fe and C contents with a surprisingly short, mean C TTs. In younger landscapes, SRO minerals are metastable and sequester C for long timescales. We hypothesize that in the KNP, SRO minerals represent a transient stage of mineral evolution and therefore lock up C for a shorter time. <br><br> Overall, we found crystalline Fe-oxyhydroxides (determined as the difference between Fe in dithionate citrate and oxalate extractions) to be the strongest predictor for soil C content, while the mean TT of soil C was best predicted from the amount of smectite, which was also related to more easily measured bulk properties such as cation exchange capacity or pH. Combined with previous research on C turnover times in 2 : 1 vs. 1 : 1 clays, our results hold promise for predicting C inventory and persistence based on intrinsic timescales of specific carbon–mineral interactions

Two new Lejeuneaceae records for the Colombian liverwort flora

Two epiphyllous Lejeuneaceae, Cololejeunea surinamensis and Drepanolejeunea polyrhiza, previously known from Amazonian Brazil, are recorded for the first time in Colombia. They were found as epiphylls on understory shrubs in the middle Caquetá area in Colombian Amazonia. Cololejeunea surinamensis was found in the Tierra Firme forests and D. polyrhiza was found in the floodplains of the Caquetá River.Dos especies de Lejeuneaceae epífilas, Cololejeunea surinamensis y Drepanolejeunea polyrhiza, previamente conocidas de los bosques amazónicos de Brasil son reportadas por primera vez para Colombia. Las especies fueron encontradas como epífilas sobre hojas de arbustos del sotobosque en el área del medio Caquetá en la amazonía Colombiana. Cololejeunea surinamensis fue encontrada en los bosques de tierra firme, mientras que D. polyrhiza fue encontrada en los planos inundables del Río Caquetá

Effect of Lipid Composition on Nanostructured Lipid Carrier (NLC) on Ubiquinone Effectiveness as an Anti-aging Cosmetics

The purpose of this research is to determine the optimum composition of solid lipid and liquid lipid in order to increase the penetration and effectiveness of Q10 as antioxidant in anti-aging cosmetics. Solid lipid and liquid lipid used in this study were cetyl palmitate and caprylic, which were combined to four (4) different ratios, namely 10:0; 9:1; 7:3 and 5:5. NLC Q10 in this study was produced by high shear homogenization method at 3400 rpm for 5 cycles and at 24000 for 1 cycle. The fourth formula was evaluated in term of characteristics, penetration and effectiveness. From the pH test , it was known that all formulas met the skin pH range (4.0-6.0). For the particle size test , all formulas (NLC 1 - NLC 4) were in the range from 269.13 to 354.77 nm with NLC 3 (7: 3) had the smallest particle size. The results of viscosity and surface tension test were also consistent with the theory, where the addition of liquid lipid reduced viscosity and surface tension of the system. The entrapment efficiency (EE) demonstrated the EE of NLC 1: 22.24%; NLC 2: 24.71%; NLC 3: 58.21% and NLC 4:36.94%. The penetration test showed all systems were able to penetrate the dermis layer at the 5th hour. NLC 3 (7:3) had more rapid onset, while the NLC Q10 with the ratio of lipid 9:1, had slower onset of action but can penetrate farther than the other NLC Q10 system. The result of Q10 effectiveness test showed NLC 2 (9:1) has lowest total macrophage (23.33) and very dense collagen observation (score : 4). From this research, it can be concluded that NLC 2 (9:1) had the most optimal lipid composition to increase the penetration and effectiveness of Q10 as an antioxidant in anti-aging cosmetics

Modeling Light-Extraction Characteristics of Packaged Light-Emitting Diodes

We employ a Monte Carlo ray-tracing technique to model light-extraction characteristics of light-emitting diodes. By relaxing restrictive assumptions on photon traversal history, our method improves upon available analytical models for estimating light-extraction efficiencies from bare LED chips, and enhances modeling capabilities by realistically treating the various processes which photons can encounter in a packaged LED. Our method is not only capable of calculating extraction efficiencies, but can also provide extensive statistical information on photon extraction processes, and predict LED spatial emission characteristics