An Algorithm for Perspective Viewing of Objects Represented by Octrees

A new algorithm is presented for viewing three-dimensional objects, represented by an octree, from an arbitrary location. The algorithm generates aperspective view of the objects while eliminating hidden surfaces. The viewer can be located anywhere inside or outside the objects. The algorithm presented in this short notefixes an artifact that is generated by a previously published algorithm due to Meagher when the viewer is located in certain regions in space. The new algorithm traverses the octree in a back-to-front order and recursively chooses correct orders for visiting the sons of non-leaf nodes.     

Reconstruction d’obstacles métalliques de forme simple

In this paper, the author presents a method that allows partial or complete reconstruction of the shape of perfectly conducting body from a multifrequency analysis of its back-scattered far-field. The method is based on the physical optics approximation. The fundamental equations are first recalled, then through the example of the sphere, the parameters of practical interest (bandwidth, number of frequencies, noisy data can be assessed). The effect of a variation of these parameters on the reconstruction process are then investigated.     

Soot formation in gas turbines using heavy fuels. 1

The aim of this study was to determine the impact of the broadening of fuel specifications on the performance of a gas turbine combustor, particularly on soot formation and oxidation, and flame tube durability. Tests were conducted with a fully-developed combustor system, the main measurements comprising total radiation, exhaust smoke and temperatures at different locations. Five fuels were used: kerosine, as aviation fuel; gas oil, as the current industrial gas turbine fuel and possible future aviation fuel; R25 (where 25 is the volume percentage of residual fuel oil in the blend with gas oil), as equivalent to crude oil now in use in many utility gas turbines; and also R50 and R70 to represent future heavier fuels. Combustor pressures were 0.3, 0.7 and 1.0 MPa. Inlet air temperatures were 313, 390 and 460 K. Primary zone air/fuel mass ratios were 12, 15 and 25. Total air/fuel ratios were 60 and 120. Attempts were made to develop a mathematical model of the soot formation-oxidation processes that occur in the system, and to include in the model some parameters to represent the change in fuel properties. In this paper, comparison of the soot formation predictions of the model with the experimental data is seen to be favourable, particularly at full power conditions.     

Diffraction par des ouvertures dans la paroi d’un obstacle conducteur. Les différentes approches usuelles du problème

The problem of electromagnetic wave interaction with conducting bodies having apertures in their surfaces is of a great practical interest and is now the purpose of great attention. The various methods described here do not present the same advantages. Thus it is interesting to review them in order to define their range of applications. The author presents rigorous and approximate methods and he illustrates them by different examples.     

双音和WCDMA调制阻塞的有效IM2分量评估

引言近年来随着第3代(3G)无线网络在日本(IMT-2000)、欧洲(UMIST)和美国(CDMA2000)的推广,3G移动手机所需的低成本、低功耗和小形状系数的用户设备(UE)变得重要起来。采用硅工艺、电路设计技术实现的直接下变频接收结构是3G手机高集成平台的一种有前途的系统方案。本文给出3G无线电的商业用全集成零中频接收机方案(图1)。广泛讨论接收机输入2阶截点(IIP2),因为它是直接变频接收机的关键性能指标。在此给出测量、仿真和计算结果。直接变频接收机结构如图1所示,直接变频或零中频接收机结构是实现接收机完全片上集成的途经,直接解调信…     

Liver microcirculation analysis by red blood cell motion modeling in intravital microscopy images

Intravital microscopy has been used to visualize the microcirculation by imaging fluorescent labeled red blood cells (RBCs). Traditionally, microcirculation has been modeled by computing the mean velocity of a few, randomly selected, manually tracked RBCs. However, this protocol is tedious, time consuming, and subjective with technician related bias. We present a new method for analyzing the microcirculation by modeling the RBC motion through automatic tracking. The tracking of RBCs is challenging as in each image, as many as 200 cells move through a complex network of vessels at a wide range of speeds while deforming in shape. To reliably detect RBCs traveling at a wide range of speeds, a window of temporal template matching is applied. Then, cells appearing in successive frames are corresponded based on the motion behavior constraints in terms of the direction, magnitude, and path. The performance evaluation against a ground truth indicates the detection accuracy up to 84% TP at 6% FP and a correspondence accuracy of 89%. We include an in-depth discussion on comparison of the microcirculation based on motion modeling from the proposed automated method against a mean velocity from manual analysis protocol in terms of precision, objectivity, and sensitivity.     

Bias voltage effect on the dielectric properties of organic–inorganic blend SiNWs elaborated via metal assisted chemical etching

The electrical proprieties of poly (3-hexylthiophene): Silicon nanowires (P3HT: SiNWs) nanocomposite was investigated by impedance spectroscopy technique. The effect of bias voltage under and without illumination was discussed. Indeed, the imaginary part of the impedance shows a high relaxation frequency related to Maxwell–Wagner–Sillars (MWS) polarization. The relaxation time was found in the range of ms and it was shifted towards high frequency with increasing the bias voltage especially at 0.6 V At bias voltage equal to V_th and under illumination, the conductivity increases because the trapped charges acquire the necessary energy to escape from the interface and the hopping time found was reduced. This indicates a change of the conduction mechanism. The Cole–Cole diagram was excellently fitted through an equivalent circuit including a chemical capacitance Cµ, a contact electrical resistance Rs and recombination resistance Rp.     

Two‐sided matching framework for optimal user association in 5G multi‐RAT UDNs

Recently, academic and industrial research communities are paying more explicit attention to the 5G multiple radio access technology ultra‐dense networks (5G multi‐RAT UDNs) for boosting network capacity, especially in UD urban zones. To this aim, in this paper, we intend to tackle the user association problem in 5G multi‐RAT UDNs. By considering the decoupled uplink/downlink access (DUDA), we divide our user association problem into two distinct subproblems representing, respectively, the uplink and the downlink channels. Next, we formulated each one as a nonlinear optimization problem with binary variables. Then, to solve them, we were restricted by the hard complexity, as well as the hard feasibility of centralized user association schemes. Thus, to resolve our user association problem in a reasonable time and distributed manner, we formulated each subproblem as a many‐to‐one matching game based on matching theory. Next, we provide two fully distributed association algorithms to compute the uplink and downlink stable matching among user equipments (UEs) and base stations (BSs). Simulation results corroborate our theoretical model and show the effectiveness and improvement of our achieved results in terms of the overall network performance, quality of service (QoS), and energy efficiency (EE) of UEs.     

Distribution of rhodium in mice submitted to treatment with the adduct of rhodium propionate and sodium isonicotinate

The distribution of rhodium in Balb/c mice following intraperitoneal (ip) administration of a solution of adduct of rhodium propionate and sodium isonicotinate has been investigated. The metal concentration was determined in blood and in the following organ tissues: brain, heart, lung, liver, spleen, kidney, testes, and uterus/ovary, and the rhodium concentration was obtained by Inductively Coupled Argon Atomic Emission Spectroscopy (ICP-AES). The metal was detected in all organ tissues examined, mainly in spleen, liver, uterus/ovary and heart. Nine days after the injection, traces of rhodium were found in the liver and kidneys and, twenty days after the injection, only in the liver.