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University of Technology Sydney. Faculty of Engineering and Information Technology. For a robot to navigate in an unknown environment, it needs to solve simultaneous localization and mapping (SLAM) problem to keep estimating its pose and, simultaneously, building a map of its surrounding environment. This thesis investigates the graph structure of SLAM and applies it in the related problems, including anchor selection and active SLAM, with the applications for Quad-rotors UAV system. First, we explore the relationship between the graphical structure of 2D and 3D pose-graph SLAM and Fisher information matrix, Cramer-Rao lower bounds, and its optimal design metrics based on the assumption of isotropic Langevin noise for rotation and block-isotropic Gaussian noise for translation. Second, we present a high-efficient greedy algorithm, using Cholesky decomposition, approximate minimum degree permutation, order re-use, and rank-1 update technologies, for the problem of choosing a set of anchored poses from a set of possible or potential poses, that minimizes estimated error in pose-graph SLAM, which is proved to be a non-normalized monotone decreasing sub-modular maximization optimization with a cardinality-fixed constraint. Third, as applications of the graph structure results, based on map joining, two active SLAM methods with two different frameworks are presented: one for 2D feature-based SLAM and the other for 3D pose-graph SLAM.

目前准确量化温室气体排放量已成为气候变化研究和政策制定的关键.在IPCC水库温室气体净通量的概念性框架下，国际水电协会汇总分析了全球223座水库的CO2和CH4研究成果，构建了G-res Tool，其可以用于评估已建或待建水库在长时间尺度下的温室气体净通量.本文介绍了G-res Tool模型的基本原理与模型框架，利用模型内置数据库中所涉及的中国长江上游12座典型水库数据进行初步应用分析，12座水库温室气体净通量平均值为88.17 g CO2e/（m2·a），在全球约7000座水库中所处水平为11.67%，处于低阈值范围.在水库温室气体净通量分析结果中，其他非相关人类活动产生的水库温室气体通量（UAS）在蓄水后总通量（Post）中所占比重远高于蓄水前温室气体通量（Pre）.长江上游水库蓄水后的CH4和CO2通量对于温室效应的贡献量相当.通过将G-res Tool模型蓄水后的温室气体通量评估结果和所涉及到的12座水库中已发表的数据对比分析发现，G-res Tool具有简便、适用面广等特点.但G-res Tool毕竟仍为经验性模型，其基本原理和模块设计上的内在缺陷在很大程度上限制了其应用范围并造成了一定的不确定性.对个案水库而言，长期跟踪观测与机理研究仍是未来减少水库温室气体净通量不确定性的关键.

The unmanned aerial vehicle (UAV) has been a research focus in recent years. The path planner is a key element of the unmanned aerial vehicle autonomous control module. In this paper, the modified wolf pack search (WPS) algorithm is applied to compute the quasi-optimal trajectories for the rotor wing UAVs in the complex three-dimensional (3D) spaces including the real and fake 3D spaces. Moreover, it adopts the multi-objective cost function. In the path planning process, some concepts in the genetic algorithm (GA) are applied to realize the WPS algorithm. Then, the crossover and mutation operators in the GA method are introduced to improve the original WPS algorithm. Considering the dynamic properties of the vehicle, the path smoothing process based on the cubic B-spline curve is used to make the planning path suitable for the fixed wing UAVs. Simulation results show that this approach is efficient for the rotor wing UAVs and the fixed wing UAVs when taking into account of all kinds of constraints and the path generated is flyable. Moreover, the comparisons of the four algorithms show that the trajectories produced by the modified WPS algorithm are far superior to the original WPS algorithm, the GA and the random search way under the same conditions.

In situ growth rates of the typical dominant algae species in Pengxi River were investigated using two kinds of in situ incubation devices(incubation cage and incubation bucket) for field incubation experiment in Lake Gaoyang of Pengxi River.Adequate nutrients,superior solar-thermal and relatively stable hydrodynamic conditions are the main characteristic of the habitat during the study.The selected environment was suitable for the algal growth and the period chosen was sensitive for the occurrence of algal blooms.During this period,in situ growth rates of Cyllotella and Cryptomonas representing phytoplankton with CR and CRS growth strategies,respectively,were both gradually declined,and those of Anabaena and Eudorina which both represent the CS growth strategies increased firstly and then declined.The in situ growth rate of Microcystis which represents the S growth strategy was negative in early days,however,the general trend of growth rate was increased.The maximum specific growth rate of each species in the incubation cage and incubation bucket were Cyllotella hubeiana 0.31,0.21 d-1,Microcystis aeruginosa 0.09,0.03 d-1,Eudorina elegans 0.16,0.42 d-1,Anabaena flos-aquae 0.30,0.26 d-1,Cryptomonas ovata 0.49,0.95 d-1,respectively.In this study,changes in the algae growth rates of the different growth strategies to a certain extent reflected the different growth trend.In addition,comprehensive analysis of the results of the performance test and in situ incubation experiment suggested that both of the two devices were able to meet the testing requirements of in situ growth rate of algae in natural water.There were potential impacts of the incubation devices on the in situ growth of phytoplankton.

In order to analyze the phytoplankton diversity in the backwater area of Pengxi River before and after the impoundment of the Three Gorges Reservoir(TGR) to the water level of 156 m,the variation of algae community of Pengxi River had been observed from July 2007 to January 2008.According to the water level variation in TGR,the time was divided into three periods: July-September,October and November-January.The algae diversity of five sites in Pengxi River was assessed using Shannon-Weaver diversity index H′.Moreover,the Connell's intermediate disturbance hypothesis was applied to analyze the impact on algae diversity caused by hydrodynamic conditions' variation during the impoundment process.Before 156m impoundment,the mean H′ index was 3.466±0.317,declined to 3.246±0.338 in October and recovered to 3.431±0.352 during the high water level period.Before impounding,the Pengxi River was of riverine-type,with flow and rainfall being the main physical disturbance factors affected the disturbance intensity and algae diversity.As a result of water level suddenly risen and the flow severely droppen,the disturbance intensity increased compared with the impounding period.After 156 m impounding,the Pengxi River was at the high water phase,the less rainfall and stable flow reduced the physical disturbance,so the H′ index recovered and maintained at a relatively stable state.

During April and May in 2010,the primary production in the Xiaojiang River backwater area,Three Gorges Reservoir was measured using the black-white-bottle method.The distribution features and relationships with light intensity,chlorophyll-a concentration(Chl.a),water temperature and partial pressure of carbon dioxide(pCO2) were studied.The results showed that the gross primary productivities(GPP) were 1927.5 mg O2/(m2·d) and 1325.0 mg O2/(m2·d) in April and May,respectively,the average value was 1626.3 mg O2/(m2·d).The gross respirations(GR) in the two months were 1037.5 mg O2/(m2·d) and 1062.5 mg O2/m2·d,respectively,and the average value was 1050.0 mg O2/(m2·d).The gross net productivities(GNP) in the two months were 890.0 mg O2/(m2·d) and 262.5 mg O2/(m2·d),and the average value was 576.3 mg O2/(m2·d).Ratio of GPP/GR were 1.86 and 1.25.These indexes suggested that the Xiaojiang River was autotrophic in the spring season.Primary productivity(P) in each depth and the ratio of productivity to respiration(P/R) had similar vertical distribution feature,showing that the maximum values occurred near the surface and they decreased with depth.Correlation analysis showed that light intensity(I) and Chl.a were significantly positive correlation with the P.Equations of the linear regression model P with Chl.a and with I were respectively: P =0.154 Chl.a-0.278,with coefficient R2=0.570,and P =0.001 I-0.013,with coefficient R2=0.942.

Zugl.: Duisburg, Essen, Univ., Diss., 2010