Journal articles on the topic 'Estimation par horizon mobile'

The paper considers the problem of tracking a moving target using a pair of cooperative bearing-only mobile sensors. Sensor trajectory optimisation plays the central role in this problem, with the objective to minimize the estimation error of the target state. Two approximate closed-form statistical reward functions, referred to as the Expected Rényi information divergence (RID) and the Determinant of the Fisher Information Matrix (FIM), are analysed and discussed in the paper. Being available analytically, the two reward functions are fast to compute and therefore potentially useful for longer horizon sensor trajectory planning. The paper demonstrates, both numerically and from the information geometric viewpoint, that the Determinant of the FIM is a superior reward function. The problem with the Expected RID is that the approximation involved in its derivation significantly reduces the correlation between the target state estimates at two sensors, and consequently results in poorer performance.

Increasing the stability and reliability of navigation for mobile objects of different classes is becoming increasingly significant. Satellite navigation systems have a fundamental defect: a vulnerability to hacking and spoofing. Observation of the horizon line is significant for two applications. The first is stellar inertial navigation systems. In this case, the horizon line can be used for local vertical estimation. Errors in local vertical estimation directly affect coordinate errors. The second is correlation-extremal navigation based on the observed horizon line shape (when islands or continents are observed from aerial vehicles). In both cases, instability of the horizon line produces navigation errors. A measurement procedure for horizon line position estimation was proposed and realised. Around-the-clock horizon line shooting was undertaken in 2013. Processing of the results shows a horizon line direction instability of about 5–7 angular minutes during the day time.

With the rapid development of the fifth-generation (5G) mobile communication technology, the application of each frequency band has reached the extreme, causing mutual interference between different modules. Hence, there is a requirement for detecting filtering and preventing interference. In the troposphere, over-the-horizon propagation occurs in atmospheric ducts and turbulent media. The effects of both ducting and turbulence can increase the probability of occurrence of long-distance co-channel interference (CCI), in turn, severely affecting the key performance indicators such as system access, handover and drop. In the 5G era, to ensure communication channels and information security, CCI must be reduced. This paper introduces a scattering parabolic equation algorithm for calculating signal propagation in atmospheric ducts on irregular terrain boundaries. It combines Hitney’s radio physical optical model and Wagner’s nonuniform turbulent scattering model for calculating the tropospheric scattering in an evaporation duct or a surface-based duct. The new model proposes a tropospheric scattering parabolic equation algorithm for various tropospheric duct environments. Finally, as a specific case, the topographical boundaries between several cities in the East China Plain were considered, and the over-the-horizon propagation loss was simulated for various ducting and turbulent environments. The simulation results were used to evaluate whether CCI would occur between cities in a specific environment.

Abstract. Nowadays it is important to shift positional accuracy of object measurements under the forest canopy closer to the accuracy standards for land surveys due to the requirements in the field of ecosystem protection, sustainable forest management, property relations, and land register. Simultaneously, it is desirable to use the technology of environmental data acquisition which is not time consuming and cost demanding. Global Navigation Satellite Systems (GNSS) are the most used for positioning today. However, the usefulness and also the accuracy of the measurements with this technology depend on various factors (the strength of the GNSS signal, the geometric position of satellites, the multipath effect etc.). Based on the above mentioned facts, the usability of technology independent of GNSS indicates an ideal solution for positioning under the forest canopy. Several studies have studied the usability of Handheld Mobile Laser Scanners (HMLS) in complex environment. The goal of this paper was to verify a new data collection approach (HMLS with Simultaneous Localization and Mapping (SLAM) technology) for the forest environment practice. The main objective of our study was to reach a precision which complies with the accuracy standards for land surveys. The RMSE of derived positions from point cloud, produced by SLAM devices were 25.3 cm and 28.4 cm, for ZEB REVO and ZEB HORIZON, the handheld mobile laser SLAM scanners used in this study. ZEB HORIZON achieved twice as big accuracy of diameter of breast height (DBH) estimation as ZEB REVO.

In this study, we evaluated the performance of GeoSLAM ZEB Horizon and Stonex X120GO SLAM handheld mobile laser scanners (HMLS) to address two primary objectives. First, we aimed to assess and compare the accuracy of positioning achieved using HMLS instruments. Second, we sought to investigate the influencing factors and their impact on estimation accuracies. The factors influencing the accuracy of positioning in HMLS Simultaneous Localization and Mapping-aided solutions were defined, considering the scanner type, distance from the trajectory, forest structure, tree species, and Diameter at Breast Height. The same type of trajectory was tested in five different stand structures. The evaluation of GeoSLAM HMLS point clouds yielded an average positional RMSE of 17.91 cm, while the data extracted from the Stonex HMLS resulted in an average positional RMSE of 17.33 cm. These results underscore the significant potential of HMLS technology in addressing the critical need for precise positioning data in various applications, from forestry management to environmental monitoring, wildlife habitat assessment, and climate change studies. By harnessing the power of handheld mobile laser scanners, our research aims to enhance the accuracy and efficiency of geospatial data capture in challenging.

Point cloud data is essential measurement information that has facilitated an extended functionality horizon for urban mobility. While 3D lidar and image-depth sensors are superior in implementing mapping and localization, sense and avoidance, and cognitive exploration in an unknown area, applying 2D lidar is inevitable for systems with limited resources of weight and computational power, for instance, in an aerial mobility system. In this paper, we propose a new pose estimation scheme that reflects the characteristics of extracted feature point information from 2D lidar on the NDT framework for exploiting an improved point cloud registration. In the case of the 2D lidar point cloud, vertices and corners can be viewed as representative feature points. Based on this feature point information, a point-to-point relationship is functionalized and reflected on a voxelized map matching process to deploy more efficient and promising matching performance. In order to present the navigation performance of the mobile object to which the proposed algorithm is applied, the matching result is combined with the inertial navigation through an integration filter. Then, the proposed algorithm was verified through a simulation study using a high-fidelity flight simulator and an indoor experiment. For performance validation, both results were compared and analyzed with the previous techniques. In conclusion, it was demonstrated that improved accuracy and computational efficiency could be achieved through the proposed algorithms.

Les travaux présentés dans cette synthèse portent essentiellement sur l'analyse de scènes à partir de caméras mobiles avec pour application immédiate l'apport d'une vision par ordinateur efficace dans les systèmes autonomes. Ils sont le fruit d'une décennie de recherches menées d'abord à l'INRETS (actuellement IFSTTAR : Institut français des sciences et technologies des transports, de l'aménagement et des réseaux ) puis à l'Université Paris Sud XI (Institut d'Électronique Fondamentale). L'idée initiale est que l'autonomie d'un système implique, ne serait-ce que pour raisons énergétiques, une faible variété d'opérateurs de perception, dont les algorithmes de vision. Les "primitives" extraites des images seront intrinsèquement robustes et stables vis-à-vis de perturbations variées. Elles doivent de plus anticiper, voire faciliter, un processus de décision à divers niveaux voulu systématique. Les lignes de niveaux répondent parfaitement à ces contraintes : on vérifie sans peine leur robustesse et leur abondance dans une image suggère et alimente un processus de décision cumulatif (manipulant un objet de décision unique : l'histogramme généralisé en espace de vote). Nos efforts se sont alors concentrés sur deux aspects : 1) le premier concerne la définition d'une méthodologie cohérente dans laquelle un processus primaire d'extraction de lignes de niveaux est enrichi afin de permettre la construction de primitives plus complexes guidée par un modèle de déformation de l'image. Le nombre de composants donc la forme des primitives est fonction directe du nombre de variables caractérisant le mouvement (déformation) à déterminer. 2) Le second intéresse une méthode de décision cumulative unifiée permettant de traiter des thèmes applicatifs de complexité croissante. Nos travaux se déclinent alors en trois niveaux de cumul, chacun associé de manière à un stade particulier de l'analyse d'images. Les thèmes applicatifs traités pour illustrer notre démarche sont de complexité croissante : détection et estimation du mouvement en caméra fixe, recalage d'images en caméra mobile (type de mouvement connu et profondeur des objets contrainte) puis estimation générale du mouvement propre et de la structure de la scène en caméras embarquées sur un véhicule mobile. Les résultats obtenus montrent comment un choix de primitives robustes associé à un processus de décision cumulatif permet la réutilisation des opérateurs dans plusieurs secteurs. Les systèmes proposés ont la particularité d'être compacts et cohérents, propriété recherchée dans les applications considérées.

The objective of the study was to develop a precise method of determination of the evaporation rate in a soil irrigated with the use of a mobile injection irrigation system. Two methods of constructing functions approximating the value of evaporation have been developed. In the first method, the domain comprises the parameters of injection irrigation, i.e., the dose and the depth of injection, and in the second, the volumetric moisture of soil in the layer immediately below the soil surface, which was measured with time-domain reflectometry (TDR) sensors. For that purpose, a laboratory experiment was carried out, based on 12 physical models. The study was conducted on a natural soil material, with particle size distribution of its mineral parts corresponding to that of a loamy sand soil. It was demonstrated that evaporation intensity increases with irrigation and decreases with increase in the depth of water application. Using TDR sensors, it was also shown that evaporation intensity increases proportionally to the weighted arithmetic mean of the volumetric moisture. Comparison of the two methods indicates that the evaporation intensity of injection-irrigated soil can be estimated with higher accuracy when the domain of the approximating function is the injection depth and dose than when the domain of the function is the weighted mean of volumetric moisture of the surface horizon of the soil. However, the method using TDR sensors for the estimation of evaporation intensity of an injection-irrigated soil has a greater potential for the construction of universal approximating models. In addition, the advantage of the method based on the use of TDR sensors is that it uses arguments for the approximating function, f2(θ˜), in real time.

Radio frequency electromagnetic radiation from base stations is the main source of electromagnetic background generated by mobile (cellular) communication systems in residential areas; its intensity makes a significant contribution to the level of electromagnetic pollution of the habitat and determines the level of electromagnetic safety of the population. The previously proposed technique for estimating the average intensity of this background, based on the analysis of the territorial intensity of mobile traffic, takes into account the spatial selectivity of base station radiation in a simplified form by introducing the radiation directivity parameter U, equal to the inverse of the number of base station service sectors, assuming that the width of the main lobe of the radiation pattern is equal to the width of this sector and without taking into account the radiation directivity in the vertical plane, which determines the pessimistic nature of these estimates. The paper presents a refined analysis of the values of the parameter U for a two-level models of antenna radiation patterns, which reflects the real values of the width of their main lobes in horizontal and vertical planes, the relative levels of side lobes and the ratio of radiation power of the main and side lobes. The analysis was performed both for stationary sector antennas of cellular communication systems and for adaptive phased antenna arrays of 4G/5G systems capable of providing service using narrow beams. The analysis showed that the value of the U parameter of sector antennas is 5–15 dB less than the inverse of the number of sectors of base stations, and for narrow beams of adaptive antenna arrays, this difference reaches 20 dB. If tilt angles of main lobes of antenna radiation patterns with respect to the horizon are less than 30°, then at estimation of the average electromagnetic background intensity the inverse of their antenna gain in the main lobe can be used as the U parameter value of the spatial selectivity (directivity) of base stations radiations.

The exponential rise in wireless technologies and allied applications has revitalized academia-industries to develop more efficient and economic routing solution to meet Quality-of-Service (QoS) provision. Amongst the major wireless communication systems, Wireless Sensor Network (WSN) is the most sought technology for defense surveillance, healthcare monitoring, industrial monitoring and control, civic and strategic infrastructure surveillance etc. Additionally, the up surge in Internet of Things (IoT) and Machine to Machine (M2M) communication systems too have broadened the horizon for WSNs based communication. However, the parallel increase in communication environment, complex network conditions etc confine efficacy of the classical WSN protocols. Dynamic network and node conditions often force classical protocols to undergo pre-mature link outage, delayed transmission, energy exhaustion and eventual QoS violation. To address such issues enhancing Median Access Control (MAC) and allied routing decision can have vital significance. However major existing efforts either focus on MAC enhancement or routing optimization, even under static WSN topology. Considering it as motive in this paper a highly robust “Cross-layer architecture based Joint-Synchronous MAC and Routing Protocol for WSN communication (JSMCRP)” has been developed. Being cross layer model JSMCRP protocol employs Application Layer, Network Layer, MAC Layer and PHY Layer to perform Network Adaptive MAC scheduling and Dynamic Routing Decision. JSMCRP employs Data Traffic Assessment, Prioritization and Scheduling (DTAPS), Proactive Network Monitoring and Knowledge (PNMK), Dynamic Congestion Index Estimation (DCIE), Adaptive Link Quality, Packet Injection Rate and Cumulative Rank Sensitive Routing Decision (CRSRD) to perform routing decision. Additionally, exploiting dynamic network/node conditions it performs Cognitive MAC scheduling to ensure QoS centric communication over IEEE 802.15.4 protocol stack. JSMCRP exhibited higher PDR, lower PLR and low delay under varying network conditions, suitable for real-time communication over constrained mobile WSN conditions.

In this work, we compared six emerging mobile laser scanning (MLS) technologies for field reference data collection at the individual tree level in boreal forest conditions. The systems under study were an in-house developed AKHKA-R3 backpack laser scanner, a handheld Zeb-Horizon laser scanner, an under-canopy UAV (Unmanned Aircraft Vehicle) laser scanning system, and three above-canopy UAV laser scanning systems providing point clouds with varying point densities. To assess the performance of the methods for automated measurements of diameter at breast height (DBH), stem curve, tree height and stem volume, we utilized all of the six systems to collect point cloud data on two 32 m-by-32 m test sites classified as sparse (n = 42 trees) and obstructed (n = 43 trees). To analyze the data collected with the two ground-based MLS systems and the under-canopy UAV system, we used a workflow based on our recent work featuring simultaneous localization and mapping (SLAM) technology, a stem arc detection algorithm, and an iterative arc matching algorithm. This workflow enabled us to obtain accurate stem diameter estimates from the point cloud data despite a small but relevant time-dependent drift in the SLAM-corrected trajectory of the scanner. We found out that the ground-based MLS systems and the under-canopy UAV system could be used to measure the stem diameter (DBH) with a root mean square error (RMSE) of 2–8%, whereas the stem curve measurements had an RMSE of 2–15% that depended on the system and the measurement height. Furthermore, the backpack and handheld scanners could be employed for sufficiently accurate tree height measurements (RMSE = 2–10%) in order to estimate the stem volumes of individual trees with an RMSE of approximately 10%. A similar accuracy was obtained when combining stem curves estimated with the under-canopy UAV system and tree heights extracted with an above-canopy flying laser scanning unit. Importantly, the volume estimation error of these three MLS systems was found to be of the same level as the error corresponding to manual field measurements on the two test sites. To analyze point cloud data collected with the three above-canopy flying UAV systems, we used a random forest model trained on field reference data collected from nearby plots. Using the random forest model, we were able to estimate the DBH of individual trees with an RMSE of 10–20%, the tree height with an RMSE of 2–8%, and the stem volume with an RMSE of 20–50%. Our results indicate that ground-based and under-canopy MLS systems provide a promising approach for field reference data collection at the individual tree level, whereas the accuracy of above-canopy UAV laser scanning systems is not yet sufficient for predicting stem attributes of individual trees for field reference data with a high accuracy.

In this paper, a generic multi-sensor fusion framework is developed for the localization of intelligent vehicles and mobile robots. The localization framework is based on moving horizon estimation (MHE). Unlike the commonly used probabilistic filtering algorithms – for example, extended Kalman filter (EKF) and unscented Kalman filter (UKF) – MHE relies on solving successive least squares optimization problems over the innovation of multiple sensors’ measurements and a specific estimation horizon. In this paper, we present an efficient and generic multi-sensor fusion scheme, based on MHE. The proposed multi-sensor fusion scheme is capable of operating with different sensors’ rates, missing measurements, and outliers. Moreover, the proposed scheme is based on a multi-threading architecture to reduce its computational cost, making it more feasible for practical applications. The MHE fusion method is tested using simulated data as well as real experimental data sequences from an intelligent vehicle and a mobile robot combining measurements from different sensors to get accurate localization results. The performance of MHE is compared against that of UKF, where the MHE estimation results show superior performance.

Objective: The objective of the present study was to develop and validate a novel reverse phase high performance liquid chromatographic (RP-HPLC) method, for simultaneous determination of ritonavir (RIT), ombitasvir (OMB) and paritaprevir (PAR) in bulk mixtures, and in tablets. Methods: Determination of the drugs ritonavir (RIT), ombitasvir (OMB), and paritaprevir (PAR), was carried out applying Hypersil BDS C18 column (250 mm X 4.6 mm i.e., 5 µm particle size), with photodiode array detector at λmax of 254 nm. The mobile phase applied for the current study composed of two solvents, i.e. A (0.01N % w/v potassium di-hydrogen orthophosphate buffer, pH 3.0 adjusted with dilute orthophosphoric acid) and B (acetonitrile). The mobile phase was pumped at a flow rate of 1.0 ml/min in the isocratic mode. The validation study with respect to specificity, linearity, precision, accuracy, and robustness, limit of detection (LOD) and limit of quantification (LOQ) was carried out employing the ICH guidelines. Results: Ritonavir, ombitasvir, and paritaprevir showed linearity of response between 12.5-75 μg/ml for ritonavir, 3.125-18.75 µg/ml for ombitasvir and 18.75–112.5 µg/ml for paritaprevir, with a correlation coefficient (R2) 0.999, 0.999,0.999 for RIT, OMB, and PAR respectively. The % recovery obtained was 99.82±0.14 % RIT, OMB 100.03±0.96 % and for 99.96±0.26 % PAR. The LOD and LOQ values for RIT, OMB, PAR were obtained to be 0.02, 0.019and0.02, µg/ml and 0.07, 0.06 and 0.07 µg/ml, respectively. The method also exhibits good robustness for different chromatographic conditions like wavelength, flow rate, mobile phase, and injection volume. Conclusion: The method was successfully employed, for the quantification of RIT, OMB, and PAR, in the quality control of in-house developed tablets, and can be applied for the industrial use.

International audience The aim of this work is to reconstitute the state of a discrete-time nonlinear system representing a dynamical model of a harvested fish population. For this end, we are going to use a numerical method of building an interval observer for the consider discrete-time model fish population. We adapt to this model an algorithm called "Interval Moving Horizon State Estimation" (IMHSE) which gives an estimated interval of the system states. This algorithm is carried out in [8] and work well for a general class of discrete-time systems. Le but de ce travail est de reconstruire les états d’un système discret non linéaire représentant la dynamique d’une population de poissons soumise à l’action de la pêche. Pour cela nous allons utiliser une méthode numérique de synthèse d’un observateur intervalle du modèle discret de la population de poissons considéré. Nous adaptons à ce modèle un algorithme appelé "Interval Moving Horizon State Estimation" (IMHSE) qui permet d’estimer les états du système par des intervalles. Cet algorithme est développé dans [8] et marche bien pour une classe générale de systèmes discrets.

Co-design and integration of vehicle navigation and control and state estimation is key for enabling field deployment of mobile robots in GPS-denied cluttered environments, and sensor calibration is critical for successful operation of both subsystems. This paper demonstrates the potential of this co-design approach with field tests of the integration of a reactive receding horizon-based motion planner and controller with an inertial aided multi-sensor calibration scheme. The reported method provides accurate calibration parameters that improve the performance of the state estimator, and enable the motion controller to generate smooth and continuous minimal-jerk trajectories based on local LiDAR data. Numerical simulations in Unity, and real-world experimental results from the field corroborate the claims of efficacy for the reported autonomous navigation computational pipeline.

Canopy-intercepted light, or photosynthetically active radiation, is fundamentally crucial for quantifying crop biomass development and yield potential. Fractional photosynthetically active radiation (PAR) (fPAR) is conventionally obtained by measuring the PAR both below and above the canopy using a mobile lightbar platform to predict the potential yield of nut crops. This study proposed a feasible and low-cost method for accurately estimating the canopy fPAR using aerial photogrammetry-based canopy three-dimensional models. We tested up to eight different varieties in three experimental almond orchards, including California's leading variety of ‘Nonpareil’. To extract various canopy profile features, such as canopy cover and canopy volume index, we developed a complete data collection and processing pipeline called Virtual Orchard (VO) in Python environment. Canopy fPAR estimated by VO throughout the season was compared against midday canopy fPAR measured by a mobile lightbar platform in midseason, achieving a strong correlation (R2) of 0.96. A low root mean square error (RMSE) of 2% for ‘Nonpareil’. Furthermore, we developed regression models for predicting actual almond yield using both measures, where VO estimation of canopy fPAR, as a stronger indicator, achieved a much better prediction (R2 = 0.84 and RMSE = 195 lb acre−1) than the lightbar (R2 = 0.70 and RMSE = 266 lb acre−1) for ‘Nonpareil’. Eight different new models for estimating potential yield were also developed using temporal analysis from May to August in 2019 by adjusting the ratio between fPAR and dry kernel yield previously found using a lightbar. Finally, we compared the two measures at two different spatial precision levels: per-row and per-block. fPAR estimated by VO at the per-tree level was also assessed. Results showed that VO estimated canopy fPAR performed better at each precision level than lightbar with up to 0.13 higher R2. The findings in this study serve as a fundamental link between aerial-based canopy fPAR and the actual yield of almonds.

Problem definition: Achieving broad access to health services (a target within the sustainable development goals) requires reaching rural populations. Mobile healthcare units (MHUs) visit remote sites to offer health services to these populations. However, limited exposure, health literacy, and trust can lead to sigmoidal (S-shaped) adoption dynamics, presenting a difficult obstacle in allocating limited MHU resources. It is tempting to allocate resources in line with current demand, as seen in practice. However, to maximize access in the long term, this may be far from optimal, and insights into allocation decisions are limited. Academic/practical relevance: We present a formal model of the long-term allocation of MHU resources as the optimization of a sum of sigmoidal functions. We develop insights into optimal allocation decisions and propose pragmatic methods for estimating our model’s parameters from data available in practice. We demonstrate the potential of our approach by applying our methods to family planning MHUs in Uganda. Methodology: Nonlinear optimization of sigmoidal functions and machine learning, especially gradient boosting, are used. Results: Although the problem is NP-hard, we provide closed form solutions to particular cases of the model that elucidate insights into the optimal allocation. Operationalizable heuristic allocations, grounded in these insights, outperform allocations based on current demand. Our estimation approach, designed for interpretability, achieves better predictions than standard methods in the application. Managerial implications: Incorporating the future evolution of demand, driven by community interaction and saturation effects, is key to maximizing access with limited resources. Instead of proportionally assigning more visits to sites with high current demand, a group of sites should be prioritized. Optimal allocation among prioritized sites aims at equalizing demand at the end of the planning horizon. Therefore, more visits should generally be allocated to sites where the cumulative demand potential is higher and counterintuitively, often those where demand is currently lower.

Abstract The Deepwater Horizon Mobile Offshore Drilling Unit (MODU) was one of several classes of floatable drilling systems. The explosion on April 20, 2010 led to fatalities and the worst oil spill in the U.S. We present an independent estimate of the oil-flow rate into The Gulf caused by the drill-pipe rupture. We employed the NASA Moderate-Resolution Imaging-Spectroradiometer (MODIS) satellite photographs, starting from the days immediately following the disaster, to determine the magnitude of spill. From these images, we obtained the surface area of the spill and calculated the oil flow rate by two different methods based on contrasting luminance within that area. The first assumes a constant thickness for the total area with upper and lower bounds for the thickness. The second separates the area into different patches based on the luminance levels of each. The probability density function (PDF) of such luminance plots showed natural groupings, allowing patches be identifiable. Each patch maps to a specific thickness. This second approach provides a more accurate average thickness. With the assumption that evaporation and other loss amounted to ∼40% of the spill, we obtained, from the first method, a flow rate ranging from 9,300 barrels per day (BPD) to 93,000 BPD. A value of 51,200 BPD was obtained using patch-separation method. This latter estimate was a plausible value, obtained from the current analysis, but with no details presented in an Extended Abstract in OMAE2012, is remarkably consistent with the “official U.S.-Govt. estimates.”

UPS, which stands for Uninterruptible Power Supply, is a supply system that acts as a bridge between the electric grid and the consumer. It consists of electric hardware components and batteries. The prima-ry purpose of UPS is to provide emergency power supply to critical locations such as hospitals, computer networks, communication systems, and industrial processes. In the current market, there are various types of UPS available, but some essential features are still miss-ing. To address this, we are working on developing a smart UPS system that includes battery backup es-timation based on load changes. This means we utilize a microcontroller and an LCD display to show the remaining life of the batteries or backup batteries. This feature allows workers to easily understand the status of the UPS and take necessary actions within the required time duration. Additionally, we have integrated a GSM module into our UPS system. This enables the system to send text messages at fixed intervals to the designated mobile device of the personnel responsible for the par-ticular UPS. This feature ensures timely communication and facilitates efficient management of the UPS. By the end of our paper, we aim to create a reliable and user-friendly UPS system that surpasses the functionalities of other UPS systems available in the market.

Vorapaxar is a protease-activated receptor-1 (PAR-1) antagonist indicated for the reduction of atherothrombotic cardiovascular (CV) events in patients with a history of myocardial infarction (MI) or with peripheral arterial disease (PAD), based on the findings of the TRA 2°P-TIMI 50 trial for patients without a history of stroke or transient ischemic attack. This analysis evaluated the health outcomes of triple antiplatelet therapy with vorapaxar when added to a standard care regimen of clopidogrel plus aspirin (ASA) in comparison with standard care alone, for patients without a history of transient ischemic attack or stroke who survived hospitalization for a qualifying MI. A cohort-level state-transition model was developed in Microsoft Excel to estimate membership in health states over a lifetime time horizon: event-free, post-MI, post-stroke, dead due to bleeding, dead due to CV causes, and dead due to other causes. Predictive equations were developed from patient-level data from TRA 2°P, in order to estimate CV event-related transition probabilities, based on patient characteristics. These improve upon Framingham risk equations as they consider the time since the most recent myocardial infarction, and they are based on a greater number of CV events from a larger and more diverse population. Meta-analyses, national statistics, and other publications were used to estimate case fatality and bleeding rates, the risk of non-CV mortality, as well as utilities for estimation of quality-adjusted life years (QALYs). For validation, the risk equation and model results were compared with the observed event rates in TRA 2°P, risk estimates from Framingham Heart Study publications, as well as QALY and life-year outcomes from other published models. Over a lifetime time horizon, the model predicted 8.3 fewer recurrent MIs, 3.8 fewer strokes, and 18.2 fewer CV deaths in the vorapaxar plus standard care arm in comparison with standard care alone, per 1,000 patients treated, with an increase of 26.4 transfusions, 3.6 intracranial hemorrhage, and 0.9 fatal bleeding events. Discounted life-years and QALYs increased by 0.4 and 0.3 respectively with vorapaxar treatment. In validation, modeled CV event counts were within 0.1% of the observed rates in TRA 2°P. The model’s prediction of 8.94 QALYs in the standard care arm is comparable to the prediction of 9.55 to 9.78 QALYs in a recent UK model of antiplatelet monotherapy after MI. Based on model results, triple antiplatelet therapy with vorapaxar provides additional clinical benefit versus standard care after MI, for a patient population that is at high risk for recurrent and potentially fatal events. In validation, the model yielded projections of CV morbidity and mortality comparable to the observed outcomes from the TRA 2°P clinical trial, Framingham equations, and other models.

1. A Minor Philosopher According to Guattari and Deleuze's definition, a 'minor literature' is the literature of a minority that makes use of a major language, a literature which deterritorialises that language and interconnects meanings of the most disparate levels, inseparably mixing and implicating poetic, psychological, social and political issues with each other. In analogy, the Japanese media theorist Toshiya Ueno has refered to Félix Guattari as a 'minor philosopher'. Himself a practicing psychoanalyst, Guattari was a foreigner to the Grand Nation of Philosophy, whose natives mostly treat him like an unworthy bastard. And yet he has established a garden of minor flowers, of mongrel weeds and rhizomes that are as polluting to philosophy as Kafka's writing has been to German literature (cf. Deleuze & Guattari, Kafka). The strategies of 'being minor' are, as exemplified by Guattari's writings (with and without Deleuze), deployed in multiple contexts: intensification, re-functionalisation, estrangement, transgression. The following offers a brief overview over the way in which Guattari conceptualises media, new technologies and art, as well as descriptions of several media art projects that may help to illustrate the potentials of such 'minor machines'. Without wanting to pin these projects down as 'Guattarian' artworks, I suggest that the specific practices of contemporary media artists can point us in the direction of the re-singularising, deterritorialising and subjectifying forces which Guattari indicated as being germane to media technologies. Many artists who work with media technologies do so through strategies of appropriation and from a position of 'being minor': whenever a marginality, a minority, becomes active, takes the word power (puissance de verbe), transforms itself into becoming, and not merely submitting to it, identical with its condition, but in active, processual becoming, it engenders a singular trajectory that is necessarily deterritorialising because, precisely, it's a minority that begins to subvert a majority, a consensus, a great aggregate. As long as a minority, a cloud, is on a border, a limit, an exteriority of a great whole, it's something that is, by definition, marginalised. But here, this point, this object, begins to proliferate ..., begins to amplify, to recompose something that is no longer a totality, but that makes a former totality shift, detotalises, deterritorialises an entity.' (Guattari, "Pragmatic/Machinic") In the context of media art, 'becoming minor' is a strategy of turning major technologies into minor machines. a. Krzysztof Wodiczko (PL/USA): Alien Staff Krzysztof Wodiczko's Alien Staff is a mobile communication system and prosthetic instrument which facilitates the communication of migrants in their new countries of residence, where they have insufficient command of the local language for communicating on a par with the native inhabitants. Alien Staff consists of a hand-held staff with a small video monitor and a loudspeaker at the top. The operator can adjust the height of the staff's head to be at a level with his or her own head. Via the video monitor, the operator can replay pre-recorded elements of an interview or a narration of him- or herself. The recorded material may contain biographical information when people have difficulties constructing coherent narratives in the foreign language, or it may include the description of feelings and impressions which the operator normally doesn't get a chance to talk about. The Staff is used in public places where passers-by are attracted to listen to the recording and engage in a conversation with the operator. Special transparent segments of the staff contain memorabilia, photographs or other objects which indicate a part of the personal history of the operator and which are intended to instigate a conversation. The Alien Staff offers individuals an opportunity to remember and retell their own story and to confront people in the country of immigration with this particular story. The Staff reaffirms the migrant's own subjectivity and re-singularises individuals who are often perceived as representative of a homogenous group. The instrument displaces expectations of the majority audience by articulating unformulated aspects of the migrant's subjectivity through a medium that appears as the attractive double of an apparently 'invisible' person. 2. Mass Media, New Technologies and 'Planetary Computerisation' Guattari's comments about media are mostly made in passing and display a clearly outlined opinion about the role of media in contemporary society: a staunch critique of mass media is coupled with an optimistic outlook to the potentials of a post-medial age in which new technologies can develop their singularising, heterogenic forces. The latter development is, as Guattari suggests, already discernible in the field of art and other cultural practices making use of electronic networks, and can lead to a state of 'planetary computerisation' in which multiple new subject-groups can emerge. Guattari consistently refers to the mass media with contempt, qualifying them as a stupefying machinery that is closely wedded to the forces of global capitalism, and that is co-responsible for much of the reactionary hyper-individualism, the desperation and the "state of emergency" that currently dominates "four-fifth of humanity" (Guattari, Chaosmosis 97; cf. Guattari, Drei Ökologien 16, 21). Guattari makes a passionate plea for a new social ecology and formulates, as one step towards this goal, the necessity, "to guide these capitalist societies of the age of mass media into a post-mass medial age; by this I mean that the mass media have to be reappropriated by a multiplicity of subject-groups who are able to administer them on a path of singularisation" (Guattari, "Regimes" 64). Guattari consistently refers to the mass media with contempt, qualifying them as a stupefying machinery that is closely wedded to the forces of global capitalism, and that is co-responsible for much of the reactionary hyper-individualism, the desperation and the "state of emergency" that currently dominates "four-fifth of humanity" (Guattari, Chaosmosis 97; cf. Guattari, Drei Ökologien 16, 21). Guattari makes a passionate plea for a new social ecology and formulates, as one step towards this goal, the necessity, "to guide these capitalist societies of the age of mass media into a post-mass medial age; by this I mean that the mass media have to be reappropriated by a multiplicity of subject-groups who are able to administer them on a path of singularisation" (Guattari, "Regimes" 64). b. Seiko Mikami (J/USA): World, Membrane and the Dismembered Body An art project that deals with the cut between the human subject and the body, and with the deterritorialisation of the sense of self, is Seiko Mikami's World, Membrane and the Dismembered Body. It uses the visitor's heart and lung sounds which are amplified and transformed within the space of the installation. These sounds create a gap between the internal and external sounds of the body. The project is presented in an-echoic room where sound does not reverberate. Upon entering this room, it is as though your ears are no longer living while paradoxically you also feel as though all of your nerves are concentrated in your ears. The sounds of the heart, lungs, and pulse beat are digitised by the computer system and act as parameters to form a continuously transforming 3-d polygonal mesh of body sounds moving through the room. Two situations are effected in real time: the slight sounds produced by the body itself resonate in the body's internal membranes, and the transfigured resonance of those sounds is amplified in the space. A time-lag separates both perceptual events. The visitor is overcome by the feeling that a part of his or her corporeality is under erasure. The body exists as abstract data, only the perceptual sense is aroused. The visitor is made conscious of the disappearance of the physical contours of his or her subjectivity and thereby experiences being turned into a fragmented body. The ears mediate the space that exists between the self and the body. Mikami's work fragments the body and its perceptual apparatus into data, employing them as interfaces and thus folding the body's horizon back onto itself. The project elucidates the difference between an actual and a virtual body, the actual body being deterritorialised and projected outwards towards a number of potential, virtual bodies that can, in the installation, be experienced as maybe even more 'real' than the actual body. 3. Artistic Practice Guattari's conception of post-media implies criss-crossing intersections of aesthetic, ethical, political and technological planes, among which the aesthetic, and with it artistic creativity, are ascribed a position of special prominence. This special role of art is a trope that recurs quite frequently in Guattari's writings, even though he is rarely specific about the artistic practices he has in mind. In A Thousand Plateaus, Deleuze and Guattari give some detailled attention to the works of artists like Debussy, Boulez, Beckett, Artaud, Kafka, Kleist, Proust, and Klee, and Chaosmosis includes longer passages and concrete examples for the relevance of the aesthetic paradigm. These examples come almost exclusively from the fields of performing arts, music and literature, while visual arts are all but absent. One reason for this could be that the performing arts are time-based and processual and thus lend themselves much better to theorisation of flows, transformations and differentiations. The visual arts can be related to the abstract machine of faciality (visageité) which produces unified, molar, identical entities out of a multiplicity of different singularities, assigning them to a specific category and associating them with particular social fields (cf. Deleuze & Guattari, Tausend Plateaus 167-91) This semiotic territorialisation is much more likely to happen in the case of static images, whether two- or three-dimensional, than in time-based art forms. An interesting question, then, would be whether media art projects, many of which are time-based, processual and open-ended, can be considered as potential post-medial art practices. Moreover, given the status of computer software as the central motor of the digital age, and the crucial role it plays in aesthetic productions like those discussed here, software may have to be viewed as the epitome of post-medial machines. Guattari seems to have been largely unaware of the beginnings of digital media art as it developed in the 1980s. In generalistic terms he suggests that the artist is particularly well-equipped to conceptualise the necessary steps for this work because, unlike engineers, he or she is not tied to a particular programme or plan for a product, and can change the course of a project at any point if an unexpected event or accident intrudes (cf. Guattari, Drei Ökologien 50). The significance of art for Guattari's thinking comes primarily from its close relation with processes of subjectivation. "Just as scientific machines constantly modify our cosmic frontiers, so do the machines of desire and aesthetic creation. As such, they hold an eminent place within assemblages of subjectivation, themselves called to relieve our old social machines which are incapable of keeping up with the efflorescence of machinic revolutions that shatter our epoch' (Guattari, Chaosmosis 54). The aesthetic paradigm facilitates the development of new, virtual forms of subjectivity, and of liberation, which will be adequate to these machinic revolutions. c. Knowbotic Research + cF: IO_Dencies The Alien Staff project was mentioned as an example for the re-singularisation and the virtualisation of identity, and World, Membrane and the Dismembered Body as an instance of the deterritorialisation and virtualisation of the human body through an artistic interface. The recent project by Knowbotic Research, IO_Dencies -- Questioning Urbanity, deals with the possibilities of agency, collaboration and construction in translocal and networked environments. It points in the direction of what Guattari has called the formation of 'group subjects' through connective interfaces. The project looks at urban settings in different megacities like Tokyo, São Paulo or the Ruhr Area, analyses the forces present in particular local urban situations, and offers experimental interfaces for dealing with these local force fields. IO_Dencies São Paulo enables the articulation of subjective experiences of the city through a collaborative process. Over a period of several months, a group of young architects and urbanists from São Paulo, the 'editors', provided the content and dynamic input for a database. The editors collected material (texts, images, sounds) based on their current situation and on their personal urban experience. A specially designed editor tool allowed the editors to build individual conceptual 'maps' in which to construct the relations between the different materials in the data-pool according to the subjective perception of the city. On the computational level, connectivities are created between the different maps of the editors, a process that is driven by algorithmic self-organisation whose rules are determined by the choices that the editors make. In the process, the collaborative editorial work in the database generates zones of intensities and zones of tension which are visualised as force fields and turbulences and which can be experienced through interfaces on the Internet and at physical exhibition sites. Participants on the Net and in the exhibition can modify and influence these electronic urban movements, force fields and intensities on an abstract, visual level, as well as on a content-based, textual level. This engagement with the project and its material is fed back into the database and influences the relational forces within the project's digital environment. Characteristic of the forms of agency as they evolve in networked environments is that they are neither individualistic nor collective, but rather connective. Whereas the collective is determined by an intentional and empathetic relation between agents within an assemblage, the connective rests on any kind of machinic relation and is therefore more versatile, more open, and based on the heterogeneity of its components or members. In the IO_Dencies interfaces, the different networked participants become visible for each other, creating a trans-local zone of connective agency. The inter-connectedness of their activities can be experienced visually, acoustically, and through the constant reconfiguration of the data sets, an experience which can become the basis of the formation of a specific, heterogeneous group subject. 4. Guattari's Concept of the Machinic An important notion underlying these analyses is that of the machine which, for Guattari, relates not so much to particular technological or mechanical objects, to the technical infrastructure or the physical flows of the urban environment. 'Machines' can be social bodies, industrial complexes, psychological or cultural formations, they are assemblages of heterogeneous parts, aggregations which transform forces, articulate and propel their elements, and force them into a continuous state of transformation and becoming. An important notion underlying these analyses is that of the machine which, for Guattari, relates not so much to particular technological or mechanical objects, to the technical infrastructure or the physical flows of the urban environment. 'Machines' can be social bodies, industrial complexes, psychological or cultural formations, they are assemblages of heterogeneous parts, aggregations which transform forces, articulate and propel their elements, and force them into a continuous state of transformation and becoming. d. Xchange Network My final example is possibly the most evocative in relation to Guattari's notions of the polyvocity and heterogenesis that new media technologies can trigger. It also links up closely with Guattari's own engagement with the minor community radio movement. In late 1997, the E-Lab in Riga initiated the Xchange network for audio experiments on the Internet. The participating groups in London, Ljubljana, Sydney, Berlin, and many other minor and major places, use the Net for distributing their original sound programmes. The Xchange network is "streaming via encoders to remote servers, picking up the stream and re-broadcasting it purely or re-mixed, looping the streams" (Rasa Smite). Xchange is a distributed group, a connective, that builds creative cooperation in live-audio streaming on the communication channels that connect them. They explore the Net as a sound-scape with particular qualities regarding data transmission, delay, feedback, and open, distributed collaborations. Moreover, they connect the network with a variety of other fields. Instead of defining an 'authentic' place of their artistic work, they play in the transversal post-medial zone of media labs in different countries, mailing lists, net-casting and FM broadcasting, clubs, magazines, stickers, etc., in which 'real' spaces and media continuously overlap and fuse (cf. Slater). 5. Heterogenic Practices If we want to understand the technological and the political implications of the machinic environment of the digital networks, and if we want to see the emergence of the group subjects of the post-media age Guattari talks about, we have to look at connectives like Xchange and the editor-participant assemblages of IO_Dencies. The far-reaching machinic transformations which they articulate, hold the potential of what Guattari refers to as the 'molecular revolution'. To realise this revolution, it is vital to "forge new analytical instruments, new concepts, because it is ... the transversality, the crossing of abstract machines that constitute a subjectivity and that are incarnated, that live in very different regions and domains and ... that can be contradictory and antagonistic". For Guattari, this is not a mere theoretical question, but one of experimentation, "of new forms of interactions, of movement construction that respects the diversity, the sensitivities, the particularities of interventions, and that is nonetheless capable of constituting antagonistic machines of struggle to intervene in power relations" (Guattari, "Pragmatic/Machinic" 4-5). The implication here is that some of the minor media practices pursued by artists using digital technologies point us in the direction of the positive potentials of post media. The line of flight of such experimentation is the construction of new and strong forms of subjectivity, "an individual and/or collective reconstitution of the self" (Guattari, Drei Ökologien 21), which can strengthen the process of what Guattari calls "heterogenesis, that is a continuous process of resingularisation. The individuals must, at the same time, become solidary and ever more different" (Guattari, Drei Ökologien 76). References Deleuze, Gilles, and Felix Guattari. Kafka: Pour une Litterature Mineur. Paris: Ed. de Minuit, 1975. ---. Tausend Plateaus. (1980) Berlin: Merve, 1992. Guattari, Félix. Cartographies Schizoanalytiques. Paris: Ed. Galilée, 1989. ---. Chaosmosis: An Ethico-Aesthetic Paradigm. (1992) Sydney: Power Publications, 1995. ---. Die drei Ökologien. (1989) Wien: Passagen Verlag, 1994. ---. "Pragmatic/Machinic." Discussion with Guattari, conducted and transcribed by Charles J. Stivale. (1985) Pre/Text 14.3-4 (1995). ---. "Regimes, Pathways, Subjects." Die drei Ökologien. (1989) Wien: Passagen Verlag, 1994. 95-108. ---. "Über Maschinen." (1990) Schmidgen, 115-32. Knowbotic Research. IO_Dencies. 1997-8. 11 Sep. 1999 <http://io.khm.de/>. De Landa, Manuel. "The Machinic Phylum." Technomorphica. Eds. V2_Organisation. Rotterdam: V2_Organisation, 1997. Mikami, Seiko. World, Membrane and the Dismembered Body. 1997. 11 Sep. 1999 <http://www.ntticc.or.jp/permanent/mikami/mikami_e.php>. Schmidgen, Henning, ed. Ästhetik und Maschinismus: Texte zu und von Félix Guattari. Berlin: Merve, 1995. ---. Das Unbewußte der Maschinen: Konzeptionen des Psychischen bei Guattari, Deleuze und Lacan. München: Fink, 1997. Slater, Howard. "Post-Media Operators." Nettime, 10 June 1998. 11 Sep. 1999 <http://www.factory.org>. Wodiczko, Krzysztof. 11 Sep. 1999 <http://cavs.mit.edu/people/kw.htm>. Xchange. 11 Sep. 1999 <http://xchange.re-lab.net>. (Note: An extended, Dutch version of this text was published in: Oosterling/Thissen, eds. Chaos ex Machina: Het ecosofisch Werk van Félix Guattari op de Kaart Gezet. Rotterdam: CFK, 1998. Citation reference for this article MLA style: Andreas Broeckmann. "Minor Media -- Heterogenic Machines: Notes on Félix Guattari's Conceptions of Art and New Media." M/C: A Journal of Media and Culture 2.6 (1999). [your date of access] <http://www.uq.edu.au/mc/9909/minor.php>. Chicago style: Andreas Broeckmann, "Minor Media -- Heterogenic Machines: Notes on Félix Guattari's Conceptions of Art and New Media," M/C: A Journal of Media and Culture 2, no. 6 (1999), <http://www.uq.edu.au/mc/9909/minor.php> ([your date of access]). APA style: Andreas Broeckmann. (1999) Minor Media -- Heterogenic Machines: Notes on Félix Guattari's Conceptions of Art and New Media. M/C: A Journal of Media and Culture 2(6). <http://www.uq.edu.au/mc/9909/minor.php> ([your date of access]).