76 research outputs found
Leveraging lighting systems with novel color sensor-based applications
No full textLighting systems are attracting many researchers and companies to investigate the potential of light beyond illumination, by creating new smart illumination systems or developing indoor positioning methods. The main challenge in realizing novel systems is to process light information in such a way that new insights are discovered. There are typically two ways to measure and process light: through photodiodes, which are cheap, but offer little information; or through cameras, which offer much information, but are expensive and create privacy issues. There is however a third type of sensor that has not been investigated much in lighting systems: color sensors. Color sensors can be viewed as a middle-of-the-road approach between photodiodes and cameras. Color sensors are inexpensive, yet provide more information than simple photodiodes.This thesis proposes two novel color sensor-based methods to enable (i) a dynamic tunable lighting system and (ii) a light-based indoor tracking system. The former allows retailers to present their merchandise in an appealing way to their customers (by adapting the light in their shops based on the products' colors). The latter makes it possible to track objects by exploiting solely their exterior color (without modulating the light source or requiring objects to carry optical receivers). Our experiments indicate that the methods we propose are able to handle the complex lighting conditions one would encounter in realizing a dynamic tunable lighting system. Furthermore, our results prove that indoor tracking of objects is possible, given that objects are sufficiently distinct in their color. The accuracy of correctly identifying, and thus tracking an object is found to be 91.4%.Electrical Engineerin
Formation de structures et phénomènes d'auto-organisation dans les décharges à barrière diélectrique
No full textLe plasma d'une décharge à barrière diélectrique (DBD) opérant dans un régime transitoire de décharge luminescente à haute pression présente dans la plupart des conditions une structure filamentaire. Cette structure filamentaire est souvent d'aspect chaotique, mais dans certaines conditions les filaments forment des motifs auto-organisés qui sont typiques des systèmes de réaction-diffusion. Le but de cette thèse est d'analyser les mécanismes de formation des motifs dans les DBD sur la base des simulations numériques et des expériences. Des expériences ont été réalisées pour deux configurations différentes d'électrode. Dans la première configuration, on peut observer les motifs en 2D au travers des électrodes transparentes. Dans la deuxième configuration, les électrodes sont linéaires ce qui permet d'observer des motifs en 1D. L'évolution spatiotemporelle de la décharge filamentaire a été analysée avec une caméra ICCD. Des modèles de décharge simples basés sur des mécanismes fondamentaux, c.-à-d. transport de dérive-diffusion couplé à l'équation de Poisson, émission secondaire par impact d'ion et ionisation en volume, peuvent reproduire, au moins qualitativement, un certain nombre d'observations expérimentales (structure hexagonale, nid d'abeilles).
Une nouvelle structure, prédite par le modèle, a été observée dans les expériences, nous appelons cette structure : la structure quinconce. Les résultats du modèle montrent l'importance de la localisation de la densité d'ion résiduelle dans l'espace à la fin d'une demi-période. Ce mécanisme joue un rôle important dans les aspects dynamiques comme la fusion, la division ou le déplacement des filaments.The plasma of dielectric barrier discharges (DBDs) operating in a transient glow discharge regime at high pressure exhibits under most conditions a filamentary structure. This filamentary structure is often chaotic in appearance, but under specific conditions the filaments form self-organized patterns that are typical of reaction-diffusion systems. The purpose of this thesis is to analyse the mechanisms of pattern formation in DBDs on the basis of numerical simulations and experiments. Experiments have been performed for two different electrode configurations of DBDs. In the first configuration, 2D patterns can be observed through the transparent electrodes. In the second configuration, the electrodes are linear and 1D patterns can be observed. The space and time evolution of the filamentary discharges was analysed with an ICCD camera in both configurations. Simple discharge models based on fundamental mechanisms, i.e. drift-diffusion transport coupled with Poisson's equation, secondary emission by ion impact and volume ionization can reproduce, at least qualitatively, a number of experimental observations (e.g hexagonal structure, honeycomb structure). An unexpected structure was predicted by the model and observed in experiments, we call this structure the quincunx structure. In this filamentary structure, the filaments of two successive half-cycles are not aligned but are shifted by half a spatial period. The model results show the importance of the localization of the remaining ion density in the gap at the end of a half-cycle. This mechanism plays an important role in some aspects of dynamical behaviour like merging, division or motion of filaments
Zhongguo xin sheng dai xiang-cheng liu dong ren kou de zhuan cheng ren yu cheng ren shen fen ren tong: ji yu Shenzhen Shi de tan suo xing yan jiu = Transition to adulthood and adult identity among Chinese young-generation rural-urban migrants : an exploratory research in Shenzhen.
No full text在以个人主义为文化核心的西方发达国家，关于个体转成人这一生命历程的研究早在二十世纪中期就已兴起。但在以家庭和关系为主导文化的中国，关于个体转成人的研究却非常少见。另一方面，在全球范围内流动人口年轻化的趋势下，已经有一些研究开始关注流动人口的转成人生命历程。但在拥有大量新生代乡-城流动人口的中国，却鲜有研究关注这一群体所处的转成人生命历程。为了弥补这些空白，本研究将探索中国新生代乡-城流动人口的转成人及其成人身份认同。作为质性研究，研究者通过目的抽样的方法获得19位来自深圳市的、具有不同人口学特征的访谈对象。通过对被访者外出、工作以及婚恋经历进行深入访谈与分析，本研究获得了非常重要的发现。首先，新生代乡-城流动人口的转成人呈现非阶段、非线性、漫长、漂泊以及高风险的特征。第二，这一群体的转成人既非个体被各样社会环境单方面影响和形塑的过程，也非具有统一的年龄界限和发展任务的发展阶段，而是能动的个体与社会环境不断互动的过程，体现出丰富的社会、文化与个体多样性。第三，在成人身份认同方面，这一群体并非单纯地将年龄的增长与社会角色的转变看作其转成人的重要标志，而是更看重自身所具备的应对城市生存挑战和满足农村家庭伦理要求的能力，呈现生存取向与伦理取向相结合的特点。本研究一方面挑战了成年初显期这一普遍运用于西方个体转成人研究中的新兴概念，另一方面，也挑战了传统的生命发展阶段视角对个体成长过程的线性的、阶段化以及标准化的理解。更重要的，本研究为中国本土关于新生代乡-城流动人口的研究提出了新的、整合的研究视角，即整合的生命历程视角。最后，研究者提倡关于新生代乡-城流动人口的社会政策与服务的设计应该具有整合的生命历程的视角，因为个体在转成人过程中的每一个选择都会影响其整个生命历程的福祉。更具体的，研究者从家庭、教育、就业、草根劳工NGO、籍制度、与社会福利制度等方面提出关于促进其转成人过程顺利进行、提高其社会福利的政策建议。Research on individuals’ transition to adulthood has emerged from the mid-20th century in Western developed countries with individualism as the core of culture. However, in China with family and relationship as the dominated culture, research regarding individuals’ transition to adulthood is rare. On the other side, research about the transition to adulthood among young migrants has sprung up under the context of global mobility in which young migrants become the major drive. However, there is little research focusing on the very transition-to-adulthood life course among young-generation rural-urban migrants in China while this age group has gradually dominated the whole rural-urban migrants. This study is to fill these research gaps.This research explored the transition-to-adulthood experience and adult identity among Chinese young-generation rural-urban migrants. As a qualitative research, the researcher obtained 19 participants in Shenzhen by purposive sampling. Through two rounds of face-to-face in-depth interview about their life experience in migration, work and intimate relationship, this research found that the transition-to-adulthood trajectory of the participants is neither linear nor progressive; it is rather prolonged, recursive, floating, and fused with instability, contingency and risks.Second, this research indicated that the transition to adulthood among the participants is neither a one-way process in which the individuals were passively influenced by social environment, nor a normative life stage with unified age ranks and developmental tasks. Rather, it is an interactive process between individual agency and different social environment and a trajectory with social, cultural and individual diversities.Third, with regard to the formation of adult identity, the participants did not consider the age and role transition as the main markers of becoming adults. On the contrary, they took high regard of the ability and responsibility in coping with survival environment in cities and fulfilling the ethic requirements and expectations from their families. In other words, their adult identity formation is both survival-oriented and ethic-oriented which was molded by their status as rural-urban migrants.This research challenged the concept of emerging adulthood which has been widely used in transition to adulthood research in western society. This research also challenged the traditional life stage perspective which understood individual’s life development as linear and normalized stages. More important, this research introduced a brand-new and more integrated research perspective ─ integrated life course - to research on young-generation rural-urban migrants in China.This research advocated that social polices targeting on the young-generation rural-urban migrants in China should be designed in integrated life course perspective because each life choice during transition to adulthood will influence the participants’ wellbeing. More specifically, the researcher proposed some key advice on policies and services in the areas of family, education and labor market, for supporting the participants’ transition to adulthood and enhancing their social welfare.Detailed summary in vernacular field only.Detailed summary in vernacular field only.Detailed summary in vernacular field only.趙瑞玲.Parallel title from added title page.Thesis (Ph.D.) Chinese University of Hong Kong, 2016.Includes bibliographical references (leaves 326-361).Abstracts also in Chinese.Zhao Ruiling
Differential immunogenicity and protective efficacy of DNA vaccines expressing proteins of Mycobacterium tuberculosis in a mouse model
No full textResearch progress of siloxane removal from biogas
No full textSiloxanes in biogas are detrimental to engine, turbine, fuel cell, etc., thus it is necessary to remove siloxanes from biogas before biogas high-value utilization. At present, there are few domestic researches and related reports in view of siloxanes removal from biogas. This paper introduces the property of siloxanes as well as sampling and analysis method, and then presents the research progress of siloxanes removal from biogas. Three commercial technologies overseas are adsorption, absorption and cryogenic condensation. Among them, adsorption on activated carbon is the most widely used method. Other technologies, such as biological removal, catalytic processes, membranes, source controlling, etc. are under exploration and development. At last, this paper summarizes the advantages and disadvantages of siloxanes removal technologies as well as the applicability and analyzes the future research trend and emphasis. This paper could provide a reference in the field of biogas high-value utilization
An Innovative Positioning System with Unsynchronized Interferometric Modulated Signals in Wireless Sensor Networks
No full textExploiting Color Sensors to Provide Optimal Lighting and Anonymous Tracking in Stores
No full textTo compete with online shopping, retailers are constantly looking for ways to improve the display of their products and to track customers to obtain shopping patterns. We propose a general framework that exploits simple color sensors on ceilings to tackle the above-mentioned challenges. Our first contribution is a tunable lighting system that estimates accurately the true color of a product, and then, adjusts automatically the type of lighting to increase the product's appeal. Based on this accurate estimation of color, our second contribution is a system to track people anonymously. Relying solely on the reflections coming from people's clothes, hair and skin, we use color sensors to generate unique optical signatures for individuals. Our evaluation shows that, in spite of the limited information provided by color sensors, the optical signatures are precise enough to differentiate people with very similar appearance except for some minor differences in their clothing.Embedded System
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