一种多模型协同的目标提取方法

固定摄像机目标提取多以高斯混合模型为背景模型,在检测运动缓慢、间歇停滞的目标时会出现前景目标空洞的问题。为此,提出一种能够适应目标间歇停滞的多模型协同目标提取方法。采用高斯混合模型进行背景学习,通过光线检测模型和场景状态检测模型协同控制背景适时更新,利用阴影检测模型剔除阴影。实验结果表明,与KaewTraKulPong P方法相比,该方法能较完整地提取到目标轮廓,且单帧处理时间较少。     

大球盖菇风味肽高效制备及其ACE抑制活性

以基料呈味特性和肽产量为指标,通过响应面工艺优化,获得大球盖菇风味肽高效制备酶解工艺,即酶解时间51.62 min,碱性蛋白酶加酶量0.99%(酶活力200 000 U/g),酶解温度42.03 ℃,底物质量浓度48.45 g/L。在传统酶解最优制备工艺基础上,采用同步超声辅助定向酶解技术制备大球盖菇富肽风味基料,平板超声辅助酶解30 min时,基料中肽含量(469.21 mg/g干重)可达到传统酶解最优条件下的产肽量,基料制备时间显著缩短;辅助酶解40 min时的产肽量(492.87 mg/g干重)较传统酶解产肽量提升了6.5%。同步超声定向酶解制备的富肽基料,在咸味和鲜味呈味特性上,分别较传统酶解基料提升了1.1~1.8倍和1.1~1.3倍。所有制备工艺得到的富肽基料均具有较优的血管紧张素转化酶(ACE)抑制活性,半抑制浓度(IC50)分别为0.071,0.074,0.122 mg/mL和0.123 mg/mL。通过对大球盖菇风味肽氨基酸序列分析发现,肽链中存在天冬氨酸(D)、缬氨酸(V)、谷氨酸(E)、亮氨酸(L)、甘氨酸(G)、精氨酸(R)、脯氨酸(P)、丙氨酸(A)的氨基酸组合肽段DD、VV、EL、VG、VE、RP、RA、RV、VR时,多肽呈现咸鲜味呈味特性。上述氨基酸组合占比较高,可能是基料呈咸鲜味的主要原因。计算机模拟分子对接技术对大球盖菇风味肽体外抑制ACE活性的预测结果显示,风味肽可与ACE活性口袋氨基酸残基形成氢键,推测这是风味肽发挥ACE抑制作用的主要原因。本研究结果为大球盖菇风味富肽基料的高效制备及开发应用提供理论依据,为制备减盐增鲜调味品、降血压功能食品或食品添加剂提供参考。     

Application of a full-scale testing facility for assessing wind-driven-rain intrusion

A new full-scale testing apparatus generically named the Wall of Wind (WoW) has been built by the researchers at the International Hurricane Research Center. The paper discusses the development of a full-scale testing methodology that can be adopted for assessing wind-driven-rain intrusion through the building envelope. The current phase of FIU's WoW is capable of testing full-scale single story building models subjected up to 56 m/s (125 mph) wind speeds and 762 mm/h (30 in./h) of rain. Emphasis has been placed on generating a wind field with a proper boundary-layer profile and turbulence characteristics. Artificial rain has been generated by continuously pumping water through a plumbing system with regularly placed spray nozzles. A large wind and wind-driven-rain field 6.7 m wide by 4.8 m high (22 ft wide by 16 ft high) has been produced, which can engulf the test specimen completely. For example, an assessment of roof secondary water barrier effectiveness in preventing water intrusion is presented. Six different roof secondary water barriers have been investigated. The amount of water intruded through the secondary water barrier and the visual observation of failure have been used as performance indexes. In addition, external and internal pressure measurements, required to explain rain intrusion mechanisms were carried out. Roof slope effects on water intrusion have been investigated by testing three different slopes (2:12, 4:12 and 6:12). Results indicated the following (i) as the slope increases the intrusion decreases, (ii) self-adhered secondary water barrier performed better than nailed secondary water barriers, and (iii) heavy secondary water barriers performed better than light secondary water barriers.     

Comparison of a New Estolide Oxidative Stability Package

The rotating pressurized vessel oxidation test (RPVOT) was used in the analysis and determination of a new oxidative stability package (OSP) for a series of estolide based materials. Three antioxidants (BHT, two different alkylated diphenyl amines) were used in either 0.5 or 1.0 wt/wt%, in different ratios, and in conjunction with one another (hindered phenol/alkylated diphenyl amines or hindered phenol/mixed alkylated diphenyl amines). The estolide-based samples analyzed for their resistance to oxidation were two pure (distilled) estolides (oleic estolide 2-EH esters and coco-oleic estolide 2-EH esters), an estolide mixture that was analyzed straight from the reaction (coco-oleic estolide 2-EH esters with coco 2-EH esters) and finally the ester fraction from the estolide mixture (coco 2-EH esters). The coco estolide mixture and coco 2-EH esters had the best overall RPVOT times with 1.0% of the alkylated diphenyl amine, coco estolide mixture, 326 min, and coco 2-EH esters, 310 min. Coco estolides were expected to have an advantage over the simple oleic estolides due to the increase in saturation in the estolide. Unexpectedly, the two distilled estolides (oleic and coco) had very similar RPVOT max times with all the antioxidants, and were much higher than the other oxidative packages tested to date. In general, the alkylated diphenyl amine outperformed mixed alkylated diphenyl amines in the majority of the individual samples tested specially the coco 2-EH esters and distilled coco-oleic estolide 2-EH esters material at 1% OSP. Overall, a series of new antioxidants were tested and compared to other commercial products. A variety of physical properties of the four estolide based material were collected and compared to commercially acceptable material. Coco-oleic estolide 2-EH esters were formulated to have excellent pour points (−36 °C), were both oxidatively and hydrolytically stable (RPVOT, 310 min), with expected good biodegradability which should help commercialization. Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable.