Uncertain Location Research Articles

Correcting the historical record for Kīlauea Volcano's 1832, 1868, and 1877 summit eruptions

Three fissure eruptions are known to have occurred along the northeastern edge of Kīlauea's summit caldera in the 19th century—in the years 1832, 1868, and 1877. Modern portrayal of these eruptions on maps and in written sources indicates that the 1832 eruption was from a fissure on the side of the Poliokeawe scarp south of Byron Ledge, the 1868 eruption was from a fissure on the southern wall of Kīlauea Iki Crater and fed a lava flow that covered the bottom of that crater, and the eruption in 1877 occurred on the floor of Keanakākoʻi Crater, as well as from a fissure of uncertain location on the east wall of the caldera below Byron Ledge. New geologic mapping and a review of historical documents and maps contradict these views. We find, instead, that: (1) the 1832 eruption discharged from a fissure on Byron Ledge (not Poliokeawe scarp), from another fissure on the southwestern wall of Kīlauea Iki Crater, and from at least one fissure along the east side of Kīlauea caldera below Byron Ledge; (2) the 1868 lava erupted through the floor of Kīlauea Iki Crater, not from a fissure in its southwestern wall; and (3) the 1877 lava erupted from Kīlauea Iki Crater's mid-wall fissure (until now believed to have opened in 1868), from the fissure previously assigned an 1832 date on Poliokeawe escarpment, and from a precisely relocated vent on the northeastern wall of the caldera. Finally, no conclusive first-hand accounts of the late 19th century eruption in Keanakākoʻi Crater were identified, leaving in doubt the often-inferred 1877 date for this event. Possible alternative dates include 1868, 1879, and 1881.

A novel dielectric breakdown apparatus for solid-state nanopore fabrication with transient high electric field.

The dielectric breakdown used to fabricate solid-state nanopores has separated the device from capital-intensive industries and has been widely adopted by various research teams, but there are still problems with low production efficiency and uncertain location. In this work, based on the transient breakdown phenomenon of nanofilms, a new type of dielectric breakdown apparatus for nanopore fabrication is reported. It integrates both nano-manipulation technology and dielectric breakdown nanopore fabrication technology. The nanometer distance detection method and circuit are introduced in detail. The generation principle and procedures of the transient high electric field are explained step by step. The characterization of the nanopores shows that this apparatus can fabricate sub-2 nm nanopores at a pre-located position. Besides, the nanopore diameter can be easily adjusted by setting the transient high electric field value.

Rule-based joint fuzzy and probabilistic networks

One of the important challenges in Graphical models is the problem of dealing with the uncertainties in the problem. Among graphical networks, fuzzy cognitive map is only capable of modeling fuzzy uncertainty and the Bayesian network is only capable of modeling probabilistic uncertainty. In many real issues, we are faced with both fuzzy and probabilistic uncertainties. In these cases, the proposed method of this paper can take into account both types of uncertainty with a new and different approach. In this method, we avoid fuzzy transformations to probabilities and vice versa, and fuzzy uncertainties and probabilities are considered jointly. For this purpose, in the original graphical model, first, the type of uncertainty of each node is identified, and accordingly two separate fuzzy and probabilistic networks are constructed. In these networks, relations between nodes are expressed in terms of a set of rules. In each network, fuzzy and probabilistic inference is individually constructed and ultimately the values obtained from each network are combined. This method has been tested on a real problem of localization in wireless sensor networks. In this case, a sensor with uncertain location should be able to predict its location from the received power of its adjacent sensors. In the given scenario, 60 sensors with uncertain locations and 121 sensors with a specific location are considered. Meanwhile, the average location error of sensors has been used to evaluate the methods. The simulation results show the efficiency of the proposed method well.

Bone-targeted oxidative stress nanoamplifier for synergetic chemo/chemodynamic therapy of bone metastases through increasing generation and reducing elimination of ROS

The treatment of bone metastases remains an enormous challenge in clinical application. Strategies utilizing reactive oxygen species (ROS) to induce cell death show great potential for enhanced cancer therapy. Thus, for the first time, a versatile alendronate (ALN)-functionalized and cinnamaldehyde (CA)-loaded nanoscale coordination polymer (denoted as CA/ALN@FcB) based on 1,1′-ferrocenedicarboxylicacid (Fc) and L-buthionine-sulfoximine (BSO) was properly fabricated as an oxidative stress nanoamplifier for synergetic chemo/chemodynamic therapy of bone metastases. With appropriate size and strong bone affinity of ALN, CA/ALN@FcB can preferentially accumulate in the bone metastatic site. In this nanoamplifier, CA can act as the ROS generator to produce ROS to damage cancer cells and boost intracellular hydrogen peroxide (H2O2) level, which can be converted into hydroxyl radical (•OH) with the catalysis of Fc via Fenton reaction. Simultaneously, glutathione (GSH) depletion mediated by BSO can inhibit ROS elimination to maintain H2O2 level and •OH amount, ultimately leading to superior antitumor effect. Both in vitro and in vivo results demonstrated the self-enhanced synergetic chemo/chemodynamic therapy of CA/ALN@FcB. Such a nanoamplifier can generate and maintain sufficient ROS without the introduced external light triggering, exactly addressing the dilemma posed by fewer light penetration as well as the uncertain location of bone metastases. This study not only provides a novel strategy to achieve excellent cancer therapy by boosting ROS generation and simultaneously inhibiting ROS elimination, but also creates the precedent for the application of chemodynamic therapy for bone metastases treatment.

Uncertain location–allocation decisions for a bi‐objective two‐stage supply chain network design problem with environmental impacts

AbstractIn the cases that the historical data of an uncertain event is not available, belief degree‐based uncertainty theory is a useful tool to reflect such uncertainty. This study focuses on uncertain bi‐objective supply chain network design problem with cost and environmental impacts under uncertainty. As such network may be designed for the first time in a geographical region, this problem is modelled by the concepts of belief degree‐based uncertainty theory. This article is almost the first study on belief degree‐based uncertain supply chain network design problem with environmental impacts. Two approaches such as expected value model and chance‐constrained model are applied to convert the proposed uncertain problem to its crisp form. The obtained crisp forms are solved by some multi‐objective optimization approaches of the literature such as TH, Niroomand, MMNV. A deep computational study with several test problems are performed to study the performance of the crisp models and the solution approaches. According to the results, the obtained crisp formulations are highly sensitive to the changes in the value of the cost parameters. On the other hand, Niroomand and MMNV solution approaches perform better than other solution approaches from the solution quality point of view.

A New Measure of Ensemble Central Tendency

Abstract Ensemble prediction is a widely used tool in weather forecasting. In particular, the arithmetic mean (AM) of ensemble members is used to filter out unpredictable features from a forecast. AM is a pointwise statistical concept, providing the best sample-based estimate of the expected value of any single variable. The atmosphere, however, is a multivariate system with spatially coherent features characterized with strong correlations. Disregarding such correlations, the AM of an ensemble of forecasts removes not only unpredictable noise but also flattens features whose presence is still predictable, albeit with somewhat uncertain location. As a consequence, AM destroys the structure, and reduces the amplitude and variability associated with partially predictable features. Here we explore the use of an alternative concept of central tendency for the estimation of the expected feature (instead of single values) in atmospheric systems. Features that are coherent across ensemble members are first collocated to their mean position, before the AM of the aligned members is taken. Unlike earlier definitions based on complex variational minimization (field coalescence of Ravela and generalized ensemble mean of Purser), the proposed feature-oriented mean (FM) uses simple and computationally efficient vector operations. Though FM is still not a dynamically realizable state, a preliminary evaluation of ensemble geopotential height forecasts indicates that it retains more variance than AM, without a noticeable drop in skill. Beyond ensemble forecasting, possible future applications include a wide array of climate studies where the collocation of larger-scale features of interest may yield enhanced compositing results.

Ten-year risks of recurrent stroke, disability, dementia and cost in relation to site of primary intracerebral haemorrhage: population-based study

BackgroundPatients with primary intracerebral haemorrhage (ICH) are at increased long-term risks of recurrent stroke and other comorbidities. However, available estimates come predominantly from hospital-based studies with relatively short follow-up. Moreover,...

Complex aperiodic mixed mode oscillations induced by crisis and transient chaos in a nonlinear system with slow parametric excitation

For dynamic systems with multiple time scales, its long-term behaviors usually present as mixed mode oscillations (MMOs). The formation of MMOs is closely related to the fast transitions evoked by the bifurcations of the fast sub-system. Up till now, most of the results reported in deterministic systems focus on periodic MMOs, namely the holistic structure of waveform shows periodicity, no matter whether the slow manifolds that the fast–slow flow follows are periodic or not. Moreover, since the motion of the fast–slow flow is modulated by the critical manifolds, qualitative influences of transient behaviors on the holistic structure of MMOs are less concerned. While in this paper, three patterns of aperiodic MMOs are analyzed based on a three-dimensional nonautonomous system under slow parametric excitation. According to the types of manifolds among which the fast transitions take place, these MMOs can be named as aperiodic “cycle-chaos-cycle” MMOs, aperiodic “cycle-chaos-cycle” MMOs with additional chaotic bursters, and aperiodic “chaos-cycle-point” MMOs. By combining the fast–slow analysis on certain time intervals and the probe into the transient chaos near boundary crisis, generation mechanisms of these MMOs are investigated. Our results show that the relative location between the boundary crisis value and the minimum of slow variable will qualitatively change the pattern of large amplitude oscillations (LAOs); thus, the composition of bursters can be decided by the intensity of transient chaos. On the other hand, the small amplitude oscillations (SAOs) evoked by interior crisis may contain inner structures related to bifurcation delay and sharding phenomenon. Particularly, interior crisis can lead to merging phenomena of chaotic attractors. Thus, when the chaotic LAOs stages are over, the fast–slow flow can transit to upper or lower branch in a irregular way, which results in the uncertain locations of SAOs.

An integrated MILP-MCDM decision framework for uncertain multi-criteria facilities location problem of glass industries

In existence of interval-valued parameters and managerial limitations, MCDM problems become more complex than their classical versions. In such cases, the classical MCDM techniques are not quite useful solution tools. This study focuses on a MCDM problem to establish the branches of a glass production company in all districts of Iran in existence of interval-valued parameters and managerial limitations. To overcome the above-mentioned difficulties, a typical decision framework is proposed. In the proposed framework, first, an interval Shannon's entropy approach is proposed to find interval criteria weights. Then a full interval TOPSIS approach is proposed to score the potential locations. Finally, using the obtained scores, a mixed integer linear programming model is developed to respect the constraints and find an optimised set of potential locations for the new branches. The proposed decision framework is validated by the real data of the case study and its sensitivity is studied in detail.

Defense Strategy for Resilient Shipboard Power Systems Considering Sequential Attacks

To increase the resilience of shipboard power systems, this paper presents an optimal defense strategy to protect critical lines against attacks. In the modeling, an attack is considered to destroy one critical bus, which may result in that all lines are connected to this bus will be out of service unless protection is enabled. Furthermore, after one true attack occurs, the network restoration is performed as soon as possible to pick up the critical loads and maintain system operation. To address the uncertain location of the attacks, a tri-level robust optimal defense strategy is set up to protect the critical lines under the worst attack. Moreover, a nested column-constraint generation method is employed to solve this model. A 60-bus shipboard power system is studied to demonstrate the effectiveness of the proposed model and the defense method.

Multisensor Poisson Multi-Bernoulli Filter for Joint Target–Sensor State Tracking

In a typical multitarget tracking (MTT) scenario, the sensor state is either assumed known, or tracking is performed in the sensor's (relative) coordinate frame. This assumption does not hold when the sensor, e.g., an automotive radar, is mounted on a vehicle, and the target state should be represented in a global (absolute) coordinate frame. Then it is important to consider the uncertain location of the vehicle on which the sensor is mounted for MTT. In this paper, we present a multisensor low complexity Poisson multi-Bernoulli MTT filter, which jointly tracks the uncertain vehicle state and target states. Measurements collected by different sensors mounted on multiple vehicles with varying location uncertainty are incorporated sequentially based on the arrival of new sensor measurements. In doing so, targets observed from a sensor mounted on a well-localized vehicle reduce the state uncertainty of other poorly localized vehicles, provided that a common non-empty subset of targets is observed. A low complexity filter is obtained by approximations of the joint sensor-target state density minimizing the Kullback-Leibler divergence (KLD). Results from synthetic as well as experimental measurement data, collected in a vehicle driving scenario, demonstrate the performance benefits of joint vehicle-target state tracking.

P6382The use of a mobile GPS-tracking system to activate volunteer first responders increases survival among patients with out-of-hospital cardiac arrest in residential areas

Abstract Background In residential areas, survival in patients with out-of-hospital cardiac arrest (OHCA) is less than one third compared with the survival in patients with OHCA in public areas. New strategies are needed to improve outcomes in residential areas. Purpose To evaluate the effect on survival in OHCA patients in residential vs. public areas, when using a mobile GPS-tracking system to activate volunteer first responders (VFRs). Methods In 2012 a mobile GPS-tracking system was brought into use by a first aid volunteer corps on a rural island with a population of about 12,000 inhabitants. In all cases of emergency calls where an emergency medical service (EMS) was requested, the system was activated. Three VFRs were recruited and successively provided with distinct VFR roles. One of the VFRs was guided to the nearest automatic external defibrillator before approaching the patient. We retrospectively screened all emergency ambulance journals in the years 2012–2017 to identify patients with OHCA. Additional information was collected from hospital records. Location was categorized as residential or public place. OHCAs witnessed by EMS, occurring at nursing homes or at uncertain locations were excluded. Clinical outcome was 30-day survival. Results During the 6-year period, there was a total of 114 OHCAs. Of these, 66 (57.9%) took place in residential areas, 16 (14.0%) in public areas and 32 (28.1%) were excluded. The 30-day survival in OHCA patients in residential vs. public areas was 15.2% and 12.5%, respectively (p=0.79). Demographic and survival results Residential area (n=66) Public area (n=16) P value Age, mean (SD) 71 (13) 69 (13) 0.14 Male sex, no. (%) 47 (71) 13 (87) 0.22 Volunteer first responder activated, no. (%) 55 (83) 15 (94) 0.30 AED arrives before EMS, no. (%) 36 (55) 9 (56) 0.34 Shock given before EMS, no. (%) 8/63 (13) 3/15 (20) 0.88 First rhythm shockable by EMS, no. (%) 11/64 (17) 3 (19) 0.63 30-day survival, no. (%) 10 (15) 2 (13) 0.79 The table shows the differences in OHCA located at residential areas versus public areas. AED: Automated external defibrillator; EMS: Emergency medical service; OHCA: Out-of-hospital cardiac arrest; SD: Standard deviation. Conclusion The use of a mobile GPS-tracking system to activate VFRs increases the 30-day survival among patients with OHCA in residential areas to a level comparable with the survival observed in public areas. Acknowledgement/Funding One year grant from Odense University Hospital's PhD Fund. One year grant from University of Southern Denmark. A 500,000 DKKR grant from TV2 Funen and OUH

Local trend discovery on real-time microblogs with uncertain locations in tight memory environments

This paper presents GeoTrend+; a system approach to support scalable local trend discovery on recent microblogs, e.g., tweets, comments, online reviews, and check-ins, that come in real time. GeoTrend+ discovers top-k trending keywords in arbitrary spatial regions from recent microblogs that continuously arrive with high rates and a significant portion has uncertain geolocations. GeoTrend+ distinguishes itself from existing techniques in different aspects: (1) Discovering trends in arbitrary spatial regions, e.g., city blocks. (2) Considering both exact geolocations, e.g., accurate latitude/longitude coordinates, and uncertain geolocations, e.g., district-level or city-level, that represents a significant portion of past years microblogs. (3) Promoting recent microblogs as first-class citizens and optimizes different components to digest a continuous flow of fast data in main-memory while removing old data efficiently. (4) Providing various main-memory optimization techniques that are able to distinguish useful from useless data to effectively utilize tight memory resources while maintaining accurate query results on relatively large amounts of data. (5) Supporting various trending measures that effectively capture trending items under a variety of definitions that suit different applications. GeoTrend+ limits its scope to real-time data that is posted during the last T time units. To support its queries efficiently, GeoTrend+ employs an in-memory spatial index that is able to efficiently digest incoming data and expire data that is beyond the last T time units. The index also materializes top-k keywords in different spatial regions so that incoming queries can be processed with low latency. In peak times, the main-memory optimization techniques are employed to shed less important data to sustain high query accuracy with limited memory resources. Experimental results based on real data and queries show the scalability of GeoTrend+ to support high arrival rates and low query response time, and at least 90+% query accuracy even under limited memory resources.

Specifying the precision of guiding features for visual search.

Visual search is the task of finding things with uncertain locations. Despite decades of research, the features that guide visual search remain poorly specified, especially in realistic contexts. This study tested the role of two features-shape and orientation-both in the presence and absence of hue information. We conducted five experiments to describe preview-target mismatch effects, decreases in performance caused by differences between the image of the target as it appears in the preview and as it appears in the actual search display. These mismatch effects provide direct measures of feature importance, with larger performance decrements expected for more important features. Contrary to previous conclusions, our data suggest that shape and orientation only guide visual search when color is not available. By varying the probability of mismatch in each feature dimension, we also show that these patterns of feature guidance do not change with the probability that the previewed feature will be invalid. We conclude that the target representations used to guide visual search are much less precise than previously believed, with participants encoding and using color and little else. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Research on Monitoring Location Model Based on Geo-Video Semantics

Abstract. With the flourishing and advancement of Smart City, security concerns arise, and the use of video surveillance system is regarded as a means of resolving security problems. The public environment of smart city shows the characteristics of multiscale and spatiotemporal, while Geo-video system has gradually become a trend solution in the monitoring field, which supports the correlation analysis of geo-video data, video content and geographical environment. But it has such a problem of the mass geographic video data: inefficient store, retrieval and linkage analysis. Therefore, Geo-video system has put forward an urgent demand for geographic video data with higher quality and lower scrap rate.The collection of geographic video data still depends on the monitoring equipment, and the picture content depends on the geographical location, frame size, frame rate, resolution, elevation and other parameters of the monitoring equipment. Therefore, the geo-video semantics are taken into account in the monitoring site selection model, and the semantic information such as the characteristics, behaviors and events of the monitoring objects are integrated into the construction of the monitoring screen, which is conducive to the event inference, information mining and correlation analysis of geo-video, and responds to the monitoring target and demand of geo-video system. In this way, it can start from the site selection and serve the overall construction of geo-video system.Considering the research hotspot and trend in the field of geo-video, we comprehensively analysed the location requirements, monitoring equipment parameters, location semantics and feature semantics of monitoring objects from the perspective of GIS, and a monitoring location model based on the semantics of geo-video has been proposed, which realized the fusion of monitoring picture and 2D map. Firstly, four typical geographic video semantic models (geographic entity, geographic scene, monitoring equipment and location principle) are analyzed to extract a set of extensible geographic video semantic classification model for monitoring location. Secondly, the geographic video semantic model is studied in combination with the research area, including monitoring requirement analysis, classification of geographic scenes and geographic entities, and description of the research area in terms of feature semantics and location semantics. Finally, generate the overlapping facets according to the monitoring candidate group and the visual field of the monitoring equipment, which are input as parameters into the set coverage model based on monitoring location. Linear programming method is used to solve the set coverage problem of regional monitoring scope, and the results are visualized in 2D or 3D.By comparing the two cases of the same method with different data and the same method with different data, it can be found that the location method based on geo-video semantics can scientifically and reasonably select the location of monitoring equipment in the research area, and changes across data and actual situation do not negatively impact the experimental results. The monitoring location method based on geo-video semantics is prospective and stable, and can overcome the problems of uncertain location results, uneven distribution and irregularity in general methods. Monitoring location model based on geo-video semantics can provide high quality geo-video data for video surveillance system and lay a foundation for security construction of smart city.

Design and In Situ Validation of a Guided Wave System for Corrosion Monitoring in Coated Buried Steel Pipes

Ultrasonic guided waves allow long-range screening of the full cross-section of pipelines and are thus ideal for corrosion detection. Systems using removable arrays of sensors for one-off inspections are nowadays widely-available. Guided wave pipeline monitoring, on the other hand, consists of using cheap, robust and usually permanently-mounted sensors to compare the present state of the structure with a previous or undamaged condition. Current application of available monitoring systems shows that robustness and defect detection capability remain a challenge, and some major oil and gas companies therefore consider monitoring to be less well-established. This paper deals with the design and testing of a system designed for monitoring buried and coated pipelines, focusing especially on the development of an array (or collar) of sensors. It starts by showing in detail the characterization of single piezoelectric transducers. Finite element modelling was then used to establish the dimensions of an array of these transducers, and to describe its wave-field generation characteristics. These results were then validated experimentally, initially in laboratory conditions; subsequently, a prototype was built and blind tested in near-operational conditions, which consisted of a buried full-scale pipe segment coated with Stopaq and polyethylene. The pipe segment was subjected to electrolytically accelerated corrosion at uncertain locations and at a rate which was unknown to the authors at LAMEF–UFRGS who were involved in data analysis. Results show that after 2 years of periodic data gathering, the collar showed good stability and robustness, and that it was able to detect corrosion defects found in the dissection of the pipe.

Completion Time Minimization With Path Planning for Fixed-Wing UAV Communications

Unmanned aerial vehicles (UAVs) have attracted increasing attention in wireless communications due to the high mobility. This paper investigates a fixed-wing UAV-to-UAV (U2U) communications system, with the aim of minimizing the information transmission time via proactively designing the UAV paths. First, we propose a general optimization framework for U2U communications, which covers the communication throughput requirement, interference from terrestrial transmitters, UAV maximum/minimum speeds and accelerations, and minimum U2U distance. To tackle the formulated optimization, the communication throughput constraint that contains uncertain locations of terrestrial transmitters is transformed into a deterministic expression with the aid of S-procedure, and the nonlinear equality constraints on the UAV paths are replaced by linear equality constraints with additional positive semidefinite matrix constraints. Then, we develop a path planning algorithm based on the exact penalty method and successive convex approximation. Furthermore, we design a heuristic path planning algorithm that solves the completion time minimization problem by iteratively addressing a series of throughput maximization problems. The proposed heuristic algorithm strikes a good tradeoff between the computational complexity and the achievable performance. Finally, the simulation results are presented to verify the proposed path planning algorithms under various parameter configurations.

The identity of Amomum trilobum and Amomum unifolium (Zingiberaceae: Alpinioideae), and description of four new related species from Vietnam

The identities of Amomum trilobum and Amomum unifolium, described from material originating from uncertain location in Indochina, are discussed. A lectotype of Amomum unifolium is designated here and epitypes with complete flowers are designated to ensure unambiguous application of both names. In addition, four new related species are presented in this paper, Amomum cinnamomeum, A. corrugatum, A. lutescens and A. miriflorum. Detailed descriptions, colour plates including flower dissections, notes on habitat and preliminary IUCN assessments are given for all six species.

Tuning of the Compositions and Multiple Activator Sites toward Single-Phased White Emission in (Ca9- xSr x)MgK(PO4)7:Eu2+ Phosphors for Solid-State Lighting.

Manipulating the distribution of rare earth activators in multiple cations' sites of phosphor materials is an essential step to obtain tunable emission for the phosphor-converted white-light-emitting diodes (pc-WLEDs). However, it remains the challenge to realize the photoluminescence tuning in the single-phased phosphor with single activator, due to the uncertain location of doped ions and adjustable crystallographic sites. Herein we reported the β-Ca3(PO4)2-type solid solution phosphors (Ca8.98- xSr x)MgK(PO4)7:2%Eu2+ ( x = 0-8.98) and the effects of replacing Ca2+ by Sr2+ ions on the phase structures and color-tunable emission were investigated in detail. Tunable color emission has been realized by manipulating the redistribution of Eu2+ ions among different cation sites with adjustable chemical environment, and the related mechanism on the local structures has been discussed. The high Ra (85) and low color temperature (CCT) (4465 K) values of the as-fabricated WLEDs lamp indicate that (Ca4.98Sr4)MgK(PO4)7:2%Eu2+ can act as a promising white-emitting phosphor for single-phased pc-WLEDs. This work provides a new insight into the tuning of the compositions and multiple activator sites toward single-phased white emission.

Robust Control Allocation in Attitude Fault-Tolerant Control for Combined Spacecraft Under Measurement Uncertainty

Attitude control of combined service-target system in the post-capture phase has received great attention. A new attitude dynamics of the combined spacecraft with reaction wheels has been established in the author's former work, however, the measurement uncertainty in attitude and angular velocity and uncertainty in the reconfiguration matrix of reaction wheels have not been considered, which may cause huge impact on the system performance. In this paper, a novel combination of disturbance-observer-based dynamic surface control under measurement uncertainty and robust control allocation due to uncertain mass center is investigated for attitude stabilization of the combined spacecraft. Firstly, considering measurement uncertainty, inertia uncertainty, actuator fault and actuator saturation, a new attitude dynamics of combined spacecraft is established. Then, a virtual controller is designed and all the states in the closed-loop system converge to a small neighborhood of zero, where the lumped disturbance is compensated by two stable nonlinear disturbance observers and adverse effect of actuator saturation is addressed by a stable compensator. Finally, in consideration of uncertain location of mass center in the reconfiguration matrix, a LMI-based robust control allocation is employed to deal with the problem of distributing the three axis torques over the reaction wheels. Numerical simulations are presented to illustrate the effectiveness of the proposed method.