停车场远程视频监控系统的设计与开发

提出和实现了一种基于嵌入式设备的停车场视频监控和车位检测方案。在嵌入式Linux操作系统下,通过调用计算机视觉库OpenCV中的图像处理函数,实现多车位的检测,检测结果保存到嵌入式数据库中。通过嵌入式设备将车位信息发送给PC或手持设备,并以图像的形式显示,达到远程车位检测的目的。本系统还移植了Mjpgstreamer实现停车场的远程视频监控。车位状态的检测采用2种判据:一是车位范围内差影的均值;二是车位区域内的边缘点数。测试结果表明,该方案可以很好地运行在嵌入式平台,为停车诱导提供支持。     

通信基站现场综合监控系统设计

针对传统监控系统功能单一、集成度低,对通信基站进行综合监控成本高、维护困难等问题,设计了一套集视频监控、消防、安防于一体的综合监控系统。系统选用i ．MX53系列MCU作为中央处理器,实现了对基站的视频监控,温度、湿度、烟雾、门磁、振动、空调室内外机断线报警,手动报警,市电及蓄电池监控,以及报警后120 s视频本地存储等功能;同时系统能够远程控制,对采集到的视频图像和报警数据通过有线网络或无线网络传输,方便实时监控和管理,实现通信基站无线组网监控。     

Preparation of halloysite nanotubes coated with Eudragit for a controlled release of thyme essential oil

Active food packaging that releases active agents can extend the shelf‐life and improve the quality and safety of food products. Essential oils have been used as natural food preservatives due to their antioxidant, antimicrobial, and anti‐insect properties. However, one of the limitations of using essential oils as active agents is their high volatility. In this study, thyme essential oil, an active antioxidant agent, was encapsulated into halloysite nanotubes (HNTs) using a vacuum process to sustain the release rate and to solidify the thyme oil (TO) from a liquid state. Moreover, the TO‐loaded HNT capsules (TO/HNT capsules) were coated with Eudragit EPO polymer to avoid burst release and to prolong the release time. The morphology of the prepared samples was characterized using SEM, TEM, and nitrogen adsorption–desorption analysis by BET method. Zeta potential and FTIR analysis were used to verify the encapsulation of the TO and the Eudragit EPO polymer coating of TO/HNT capsules. After Eudragit EPO polymer coating of TO/HNT capsules, the surface charge of the samples was converted from ?17.5 ± 0.2 mV to +19.4 ± 1.5 mV. The amount of encapsulated TO was determined using a GC‐FID. Encapsulation efficiency and payload of TO/HNT capsules prepared using 26.7% (w/v) TO solution were 14.94% and 14.58%, respectively. The encapsulated TO was released in a sustained manner for 96 h. In addition, antioxidant activity of the samples was evaluated using a DPPH assay and a reducing power assay. In both two assays, the antioxidant activity of the TO/HNT capsules was increased along with the increasing concentration of TO/HNT capsules. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42771.     

基于Minim OSD的水质采样船状态反馈的研究与实现

APM是国外的一个飞控系统,由于是完全开源的,因此受到广大航模爱好者的喜爱。 Minim OSD是APM系统专用的作为人机交互的视频显示模块,其在整个飞控系统中显得尤为重要。本文介绍了Minim OSD的工作原理并根据它的工作原理介绍了一种方法,将其成功移植到水质采样船中,来实现采样船各状态的反馈。     

The Effect of Active Packaging on Microbial Stability and Quality of Chinese Steamed Bread

The present study was conducted to evaluate the effect of active packaging [oxygen absorber (OA) or oxygen absorber combined with ethanol emitter (OA + EE)] on microbial stability and quality of Chinese steamed bread (CSB) stored at 25 °C. Air‐packaged CSB was taken as control. Microbiological, sensory, physical, thermal and mechanical changes were monitored as a function of treatment and storage time. On day 2 of storage total plate count was reduced by 3.1, 3.7 and 4.4 cfu/g by OA, OA + EE (1% v/v) and OA + EE (3% v/v), respectively (p < 0.05). Yeasts and moulds were inhibited during the entire storage period. No detrimental effects of OA + EE (1% v/v) were observed on organoleptic parameters, whereas OA + EE (3% v/v) gave a strong objectionable flavour and taste. Active packaging significantly (p < 0.05) delayed the increase of potential of hydrogen as compared to the control. No significant effect of active packaging was found on moisture content, water activity, colour and specific volume. An increase in the melting enthalpy of amylopectin crystallite was observed in all samples during storage. The stored CSB samples packaged with OA showed higher values of hardness compared to samples packaged with OA + EE (1% v/v), indicating the potential of ethanol as plasticizer of the protein network. The results indicate the potential application of OA and OA + EE (1% v/v) as an antimicrobial packaging system for CSB preservation. Copyright © 2015 John Wiley & Sons, Ltd.     

Combine Effects of Essential Oils and Packaging on Smoked Rainbow Trout Stored 4°C

In this study, the effect of essential oils (thyme and clove) and packaging treatments (vacuum and modified atmosphere) on the storage of hot smoked rainbow trout (Oncorhynchus mykiss) fillets over a period of 120 days at 4°C was investigated. Fillets were subjected to microbiological (total aerobic mesophilic bacteria, psychrotrophic bacteria, lactic acid bacteria, yeast and mould), chemical analyses (pH, thiobarbituric acid reactive substances and total volatile base nitrogen) and quality testing throughout the storage period. Difference in microbiological and chemical changes between samples was found to be significant (p < 0.05) during storage period. Sensory evaluation showed significant differences between the samples, and V2 and M2 samples were assessed as the most acceptable products by the panellists. In conclusion, essential oils treatment to hot smoking had a positive effect on shelf life of rainbow trout, especially clove oil showed more positive effect when compared with thyme oil. Copyright © 2015 John Wiley & Sons, Ltd.     

Using Combined Bipolar Semantic Scales and Eye‐Tracking Metrics to Compare Consumer Perception of Real and Virtual Bottles

Three‐dimensional virtual representations of consumer products are expected to gain relevance in e‐commerce applications as low cost virtual reality headsets arrive on the market in the next years. However, there are a limited number of studies related to the perceptual evaluation of virtual products and their packaging where virtual and real (photographic) representations are compared. As part of an extensive exploration toward understanding product perception in virtual stores, this work presents a study with 38 participants in which consumer perceptions of a photographic and a virtual representation of a beer bottle are examined. Perceptual evaluation is assessed using two metrics: first, an evaluation was performed by applying a bipolar semantic scale based on four axes: novelty, resolution, style and emotion. Second, eye‐tracking metrics were employed to analyse participant gaze behaviour during the visualization of stimuli. Virtual bottles were modelled using a medium polygonal load (5 K polygons per bottle), and render quality was also medium to intentionally recreate the computing limitations of smartphone‐based virtual reality headsets. Results show that a medium render quality alters consumer perception and responses using semantic scales. Eye‐tracking analysis confirms that the orientation of the bottle and how it is presented also affect consumer perception. While some orientations result in similar eye‐tracking metrics, others show different results. Copyright © 2015 John Wiley & Sons, Ltd.     

Microperforation of Three Common Plastic Films by Laser and Their Enhanced Oxygen Transmission for Fresh Produce Packaging

Three different plastic films of biaxially oriented polypropylene (BOPP), biaxially oriented polyethylene terephthalate (BOPET) and low‐density polyethylene (LDPE) were perforated using Nd‐YAG laser. Effects of laser pulse energy were examined by varying energies from 50 to 250 mJ where the pulse duration and pulse repetition were kept constant at 10 ns and 1 Hz, respectively. It was found that perforation diameters of all films increased with increasing pulse energies. Observed perforations were different among the three film types. Explanation was contributed to material inherent property and its interaction with laser. Incorporation of an inorganic filler (i.e. silica based anti‐blocking agent used in packaging film) of 0.5 wt% into the LDPE films (0.5Si‐LDPE) could improve perforation performance for LDPE. This was attributed to an increased thermal diffusivity of the 0.5Si‐LDPE film. Commercial BOPET and BOPP films containing 97 microholes/m² (hole diameter of ~100 µm) showed an improvement in oxygen transmission rates (OTR) of 18 and 5 times that of the neat films without perforation. In the case of perforated 0.5Si‐LDPE films having similar perforations of 97 microholes/m² and perforation diameter of 100 µm, a two‐fold increase of OTR was obtained. Gas transmission rates of the microperforated films were measured based on the static method. Measured OTR and CO₂TR values of the three films with varying perforation diameters in a range of ~40–300 µm were compared and discussed. Overall results clearly indicate that perforation by laser is an effective process in developing breathable films with tailored oxygen transmission property for fresh produce packaging. Copyright © 2014 John Wiley & Sons, Ltd.     

Modified Atmosphere Packaging of Guava Fruit

Fully matured fresh guava fruits (Lucknow‐49) were precooled at 10 °C for 1 h and pretreated with 500‐ppm benomyl for 5 min. The fruits were packed in 25‐µm and 50‐µm LDPE bags with active modified atmosphere packaging of 3% O₂ + 5% CO₂, 6% O₂ + 5% CO₂ and 9% O₂ + 5% CO₂ gas concentrations and stored at 5 ± 1 °C and 10 ± 1 °C temperatures as well as non‐packaged as control. The shelf life of guava could be increased up to 42 days by packaging in 50‐µm LDPE bags with a gas concentration of 9% O₂ + 5% CO₂ and stored at 10 °C without much change in physical, biochemical and sensory characteristics. Physico‐chemical changes viz., PLW, pulp to peel ratio, firmness, TSS, total sugar, ascorbic acid and titratable acidity were observed minimum for fruits packed in 50‐µm LDPE bags at 3% O₂ + 5% CO₂ gas concentration at 5 °C storage temperature, but sensory score decreased drastically after 21 days of storage. Chilling injury was observed for the fruits packed at 5 °C storage temperature after 21 days of storage, and it was severe in 25‐µm LDPE bag at later stage. Control fruits over‐ripened with the highest weight loss (12.47%) on 6 days of storage and discarded from the storage. Copyright © 2014 John Wiley & Sons, Ltd.     

Use of Sodium Lactate and Modified Atmosphere Packaging for Extending the Shelf Life of Ready‐to‐Cook Fresh Meal

In this work, the combined effects of sodium lactate and modified atmosphere packaging (MAP) in extending the shelf life of a ready‐to‐cook fresh skewer, made up of raw pork chops and semi‐dried vegetable mix (i.e. zucchini, peppers and tomatoes), were investigated. In the first experimental step, a sodium lactate solution was used to dip pork chops at three different concentrations: 20, 40 and 60% w/w. The second part of the work was focused on the use of MAP. In particular, the following MAPs were tested: MA1 (50%O₂/30%CO₂/20%N₂), MA2 (70%O₂/30%CO₂), MA3 (30%O₂/70%CO₂) and MA4 (30%O₂/30%CO₂/40%N₂). Finally, the optimal concentration of sodium lactate and the best gas composition were combined. The samples were stored at 4 °C; their microbial and sensory qualities were monitored along the entire observation period. The results indicate that the shelf life of the investigated ready‐to‐cook meal can be extended by approximately 83%, if compared with the control skewer packaged in air. The best preservation strategy is the combination of dipping of meat pieces in 40% sodium lactate solution and packaging under MA1. Copyright © 2014 John Wiley & Sons, Ltd.