Search

The High Luminosity phase of the Large Hadron Collider will deliver 10 times more integrated luminosity than the existing collider, posing significant challenges for radiation tolerance and event pileup on detectors, especially for forward calorimetry. As part of its upgrade program, the Compact Muon Solenoid collaboration is designing a high-granularity calorimeter (HGCAL) to replace the existing endcap calorimeters. It will feature unprecedented transverse and longitudinal readout and triggering segmentation for both electromagnetic and hadronic sections. The electromagnetic section and a large fraction of the hadronic section will be based on hexagonal silicon sensors of 0.5-1 cm2 cell size, with the remainder of the hadronic section being based on highly-segmented scintillators with silicon photomultiplier readout. The intrinsic high-precision timing capabilities of the silicon sensors will add an extra dimension to event reconstruction, especially in terms of pileup rejection. First hexagonal silicon modules, using the existing Skiroc2 front-end ASIC developed for CALICE, have been tested in beams at Fermilab and CERN in 2016. We present results from these tests, in terms of system stability, calibration with minimum-ionizing particles and resolution (energy, position and timing) for electrons, and the comparisons of these quantities with GEANT4-based simulation. © 2018 CERN for the benefit of the CMS collaboration.. Nuclear Physics Collegio Ghislieri di Pavia China Medical University, Taiwan Institute for Research in Fundamental Sciences aInsitute for High Energy Physics, Beijing, China bLaboratoire Leprince-Ringuet, Palaiseau, France cOrganization for Microelectronics design and Applications (OMEGA), Palaiseau, France dSaha Institute of Nuclear Physics, Kolkata, India eTata Institute for Fundamental Research, Bombay, India fUniversity of Pavia, Pavia, Italy gCERN, Geneva, Switzerland hNational Central University, Chung-Li, Taiwan iNational Taiwan University, Taipei, Taiwan jCukurova University, Adana, Turkey kImperial College of Science, Technology and Medicine, London, U.K. lBoston University, Boston, U.S.A. mCalifornia Insitute of Technology, Pasadena, U.S.A. nCarnegie Mellon University, Pittsburg, U.S.A. oFermi National Accelerator Laboratory, Batavia, U.S.A. pFlorida State University, Tallahassee, U.S.A. qNorthwestern University, Evanston, U.S.A.

The main aim of this study is to simulate the response of a micro-PEMFC numerically by utilizing a 3-D FEM model while the micro-PEMFC was assembled by three pairs of bolt along the upper and lower portions, respectively, of the end plates. The effects of different bolts locking sequences on the deformation and pressure distributions at flow-channel plates in a micro-PEMFC were investigated. The simulated results showed that if one locked the middle bolt either on the upper or lower portion first, then the obtained warpage, uniformities of deformation and von Mises equivalent stress were superior than those results if one locked either one of the four corner bolts first. Also, among the three pairs of bolts used for assembling the cell, the first locking bolt of the first pair of locking bolt and the first locking bolt of the rest of two pairs of locking bolt were to minimize the warpage and stress should locate on the different portions of the end plates.

A novel backside-illuminated CMOS image sensor (BSI-CIS) scheme and process are developed and demonstrated. This innovative scheme can be realized without fusion oxide bonding and through-silicon via (TSV) fabrication. This wafer-level TSV-less BSI-CIS scheme includes transparent ultrathin silicon $(\sim\hbox{3.6} \ \mu\hbox{m})$ and uses several bonding technologies. The characterization and assessment results indicate that the integration scheme possesses excellent electrical integrity and reliability. In addition, good quality results of the image functional test demonstrate the excellent performance of this scheme. This novel scheme also provides a realizable low-cost solution for the next-generation CIS and further 3-D novel BSI-CIS scheme.

SUMMARY This paper presents a new DC/DC converter with series half-bridge legs for high voltage application. Two half-bridge legs connected in series and two split capacitors are used in the proposed circuit to limit the voltage stress of each active switch at one-half of input voltage. Thus, active switches with low voltage stress can be used at high DC bus application. In the proposed converter, two circuit modules are operated with an interleaved pulse-width modulation scheme to reduce the input and output ripple currents and to achieve load current sharing. In each circuit module, two resonant tanks are operated with phase-shift one-half of switching cycle such that the frequency of the input current is twice the frequency of the resonant inductor current. Based on the resonant behavior, all MOSFETs are turned on at zero voltage switching with the wide ranges of input voltage and load conditions. The rectifier diodes can be turned off at zero current switching if the switching frequency is less than the series resonant frequency. Thus, the switching losses on power semiconductors are reduced. The proposed converter can be applied for high input voltage applications such as three-phase 380-V utility system. Finally, experiments based on a laboratory prototype with 960-W rated power are provided to demonstrate the performance of proposed converter. Copyright © 2011 John Wiley & Sons, Ltd.

In this study, thin wafer handling of 300mm wafer for 3D IC Integration is investigated. Emphasis is placed on the determination of the effect of a dicing tape on thin-wafer handling of wafers with Cu-Au pads, Cu-Ni-Au UBM, and TSV interposer with RDL. Also, thin-wafer handling critical issues such as the chip/interposer wafer, carrier wafer, temporary bonding, thinning, backside process, de-bonding, and assembly are presented and their potential solutions are discussed. Finally, state-of-the-art of materials and equipments for thin-wafer handling are examined.

The feasibility of a 3D IC integration SiP has been demonstrated in this investigation. The heart of this SiP is a TSV (through-silicon via) interposer with RDL (redistribution layer) on both sides, IPD (integrated passive devices) and SS (stress sensors). This interposer is used to support (with microbumps) a stack of four memory chips with TSVs, one thermal chip with heater and one mechanical chip with SS, and then overmolded on its top side for pick and place purposes. The interposer’s bottom-side is attached to an organic substrate (with ordinary lead-free solder bumps), which is lead-free solder-balled on a PCB (printed circuit board). Key enabling technologies such as TSV etching, chemical mechanical polishing (CMP), thin-wafer handling, thermal management, and microbumping, assembly and reliability are highlighted.

People use cars so frequently that they always consider the air-conditioning, and thermal comfort of the driver and passenger when buying a new car. Therefore accurate simulation of the thermal performance of automobile air conditioners to improve human comfort has become increasingly important. In order to improve the thermal comfort of passengers, 3-D flow motion and thermal behavior within vehicles must be analyzed. In this paper, a numerical simulation was used to investigate thermal behavior in a vehicle. Because air temperature at an air vent is related to the cooling capacity of the air conditioner, the cooling capacity was calculated using ɛ-NTU (effective number of transfer unit) theoretical equations. Using the air temperature relationship between inlet and outlet vents as boundary conditions, a 3-D unsteady κ-ɛ turbulent model was used to give a transient analysis simulation of the temperature field and flow conditions in a vehicle’s passenger cabin. Cooling cycle analysis and conjugate heat transfer analysis at the inside surface of the cabin’s ceiling, floor and sides were also considered. The predicted temperature distributions in the vehicles passenger cabin were in good agreement with those obtained experimentally.

In this research, a new structure and process integration for backside illuminated CMOS image sensor by using thin wafer handling technology is proposed. First of all, the wafer of a 3 Mega pixel CMOS image sensor is temporary bonded to a silicon carrier wafer with thermal plastic material and ZoneBond technology. Then the CMOS wafer is thinned down to less than 5 µm for light detection from the backside. After thinning process, the backside is permanently bonded to a 500μm-thick glass carrier substrate with a transparent thermal set bonding material. After thinning, the total thickness variation of 1μm is obtained because the thermal plastic material flow during bonding process resulted in excellent thickness uniformity. The proposed backside illuminated CMOS image sensor structure and process integration are processed in wafer level, therefore enabling a low cost technology which can be manufactured using existing infrastructure. In the assembly process of CMOS image sensor stack, firstly the analog-to-digital conversion chip was stacked onto the image signal processor chip by thermal compression bonding. Optimized bonding conditions of 250 ℃/5 sec under the bonding force of 13N were chosen and determined. Subsequently, after the stack of analogto-digital conversion chip onto the image signal processor chip, the CMOS image sensor chip was bonded onto the image signal processor/analog-to-digital conversion stack. To connect all the solder bumps between CMOS image sensor and analog-to-digital conversion chip, the higher bonding force of 18N was selected. Joined-well solder joints between these two chips could be achieved. Finally, the stacked CMOS image sensor module was attached to a print circuit board by adhesive material and wire bonding was conducted to finish the electrical connectivity between CMOS image sensor stack and print circuit board.

In this research, a new structure and process integration for backside illuminated CMOS image sensor by using thin wafer handling technology is proposed. First of all, the wafer of a 3 Mega pixel CMOS image sensor is temporary bonded to a silicon carrier wafer with thermal plastic material and ZoneBond technology. Then the CMOS wafer is thinned down to few microns to detect the light from the backside. The backside is then permanently bonded to a glass carrier substrate with a transparent thermal set bonding material. After the glass permanent bonding process, the temporary bonded silicon carrier could be removed. Cu/Sn micro-bump is fabricated at the front-side of the CMOS image sensor, thus no TSVs are needed in the proposed structure. A 3 Mega pixel CMOS wafer with micro-bumps bonded on 500µm-thick glass wafer is demonstrated. Void-free bonding is obtained both in temporary bonding and permanent bonding processes. The thickness of the CMOS image sensor wafer is less than 10 µm after thinning and the total thickness variation is around 1 µm. Thermal plastic material is used for temporary bonding because it flows during bonding process and resulted in excellent planarization. From the cross-section SEM image, Cu/Sn micro-bump is formed at the front-side of the CMOS image sensor and the ENIG UBM is formed on the front side of the Analog-to-Digital Conversion wafer. A 3 Mega pixel image is captured and demonstrated in this research. The proposed backside illuminated CMOS image sensor structure and process integration are processed in wafer level, therefore enabling a low cost technology which can be manufactured using existing infrastructure. By using thin wafer handling technology, direct fusion bond and TSV processes are not needed which provides a low cost wafer level solution.

In this letter, a new transport layer mechanism is proposed to improve the performance of transport control protocol (TCP) in mobile networks. The proposed mechanism is comprised of two parts: a loss classifier (LC) and a congestion window extrapolator (CWE). Based on LC, the cause of packet loss during roaming is determined. If the loss is considered to be caused by congestion in the wireline, the congestion window is halved; otherwise, the packet is considered to be lost in the last hop, the wireless portion, and the sender adjusts the size of the congestion window based on CWE. We conduct simulations to evaluate the performance of the proposed mechanism. The results show that our mechanism significantly improves TCP performance as compared with existing solutions for mobile networks.

Through glass via (TGV) interposer fabrication processes are critical techniques in 3D-IC integration, providing the short interconnection among different stacked chips and substrate. Nowadays, silicon is a mature material in semiconductor technology, but glass, a dielectric material, provides an attractive option due to its intrinsic characteristics for the advantages of electrical isolation, better RF performance, flexibility with CTE and most importantly low cost solution. In this investigation, the glass interposer by using TSV industry equipment and tooling was evaluated and developed and there are many challenges for processing. For process, the major differences between Glass and Si interposer are method for via formation and isolation. The test vehicle for Glass interposer is successfully processed. Glass material is composed with SiOx, it is good isolation for electrical current. The polymer-based PBO is used for passivation. For structure of glass interposer, there is one RDL on the front-side and backside, respectively. The other structure is 2 RDL on the front-side and one RDL one the backside. The CD of through glass via is 30 μm, it is formed by Corning Co. Cu overburden and Ti barrier are removed by wet etching process. For top RDL (line-width = 20μm), Cu plating process with seed layer (Ti/Cu) wet-etching process is applied. The PBO material is used for passivation, the process temperature is blow 200°C. Top UBM (15μm in diameter; 4μm/5μm-thick Cu/Sn) is formed with a top passivation opening (15μm). The structure is analyzed and demonstrated by SEM analysis. All the results indicate that the glass interposer with polymer passivation can be preceded and the cost for process is cheaper than Si interposer.

Primary approach of 3DIC packaging usually adopts organic substrates or silicon interposer as the intermedium between multi-integrated circuits (ICs) and printed circuit board. Current organic substrates face the limitations in poor dimensional stability, trace density and CTE mismatch to silicon. Silicon interposer is a good solution for high-pin-count ICs and high performance applications based on the mature Si technology of advance via formation and fine line Cu damascene multilevel interconnection process, but silicon interposer is limited by high cost. Glass is proposed as ideal interposer material due to high resistivity, low dielectric constant, low insertion loss and adjustable coefficient of thermal expansion (CTE) for the 3DIC assembly integration and most importantly low cost solution, [1-4]. The main focus of this paper is on (a) TGV electrical design, simulation and characterization, (b) wafer level integration in TGV formation, two RDL on the front-side, one RDL on the backside and polymer-based PBO for the passivation, (c) assembly process of silicon chip stack on the glass interposer with Kelvin resistance measurement. The glass interposer was assessed to have excellent electrical characteristics and is potentially to be applied for 3D product applications.

This paper presents a new zero-voltage switching (ZVS) DC/DC converter with three resonant tanks for high input voltage and high load current applications. Two series half-bridge legs and two split capacitors in order to limit the voltage stress of active switches at a half of input voltage. These resonant circuits are operated by an interleaved PWM scheme. The output sides of these resonant circuits are connected in parallel to evenly distribute the input power, lessen current stresses on rectifier diodes and reduce copper losses of transformers. The ZVS turn-on through power switches and zero-current switching (ZCS) turn-off for rectifier diodes are accomplished through three series resonant tanks. Therefore, switching losses of MOSFETs and reverse recovery problem of rectifier diodes are reduced. The primary windings of two transformers are series-connected to balance the secondary winding currents. Finally, experiments based on a scale-down prototype are provided to verify the performance of the proposed converter.

This paper describes the development status of a prototype supervised intelligent robot for space application for purposes of (1) helping the crew of a spacecraft such as the Space Station with various tasks such as holding objects and retrieving/replacing tools and other objects from/into storage, and for purposes of (2) retrieving detached objects, such as equipment or crew, that have become separated from their spacecraft. In addition to this set of tasks in this low Earth orbiting spacecraft environment, it is argued that certain aspects of the technology can be viewed as generic in approach, thereby offering insight into intelligent robots for other tasks and environments. Some candidate requirements for the space applications are presented which will be refined by the results of the prototype development and evaluation testing. Our development approach is described, including space simulation environments used in developmental testing. Candidate software architectures and their key technical issues which enable real work in real environments to be accomplished safely and robustly are addressed. Results of computer simulations of retrieving detached objects, including the situated reasoning/reaction plan approach used, are presented, as well as the results of an air bearing floor simulation of retrieving detached objects. Also described are characterization results on the usable reduced gravity environment in an aircraft flying parabolas (to simulate weightlessness) and results on hardware performance there. These results show it is feasible to use that environment for evaluative testing of dexterous grasping based on real-time vision of freely rotating and translating objects.

The goal of temporary wafer bonding for 3DIC thin wafer handling is less topographic issues and high temperature resistance. The wafer thinning and process in vacuum chamber with high temperature are the key for the 3DIC thin wafer handling. In this article a quick adhesive selecting methods, and process improvement results are evaluated and discussed.

Cerebral endothelial cells are quiescent under normal conditions; they are stimulated to proliferate around an infarct, although the mechanism is unclear. In the present study we explored the relation between angiogenesis and the expression of basic fibroblast growth factor (bFGF) by participating cells in brain infarct. Brain infarct was created in rats by ligation of a branch of the left middle cerebral artery followed by permanent occlusion of the left common carotid artery and temporary occlusion of the right common carotid artery. The brains were removed after 1 to 14 days and studied with histological and immunohistochemical methods. Bromodeoxyuridine (BRdU) was used as an S-phase marker for the proliferative cells. Enhanced bFGF immunoreactivity was observed in neurons adjacent to the infarct after 1 day, and the change subsequently spread to distant neurons in the ipsilateral hemisphere. After 2 days blood vessels and glial cells around the infarct began to incorporate BRdU. During the first week new capillaries accompanied by macrophages extended into the infarct. The macrophages, endothelial cells, and reactive astrocytes expressed mild to moderate bFGF immunoreactivity. The spatial and temporal correlation between bFGF expression and angiogenesis in conjunction with the well-known biological properties of bFGF suggest that bFGF produced by neurons, macrophages, and glial cells may participate in angiogenesis in brain infarct.

Churg-Strauss syndrome (CSS), or allergic granulomatous angiitis, is an uncommon vasculitic syndrome that is found mainly in middle-aged adults. We describe a 15-year-old girl with CSS, diagnosed by histological findings and characteristic clinical features. The patient experienced two episodes of catastrophic gastrointestinal vasculitis, resulting in resection of 150 cm of small intestine and right hemicolectomy. Colonoscopic examination showed multiple colonic ulcers with active bleeding. The clinical course of the patient was grave and refractory to the therapy of steroid and cytotoxic drugs. In the world literature only two patients with multiple colonic ulcers caused by CSS have been reported, and very rare cases of childhood-onset CSS have been published. We reviewed CSS in children and found that the prognosis was poorer than that in adults.

A methodology has been developed for the analysis of operational flexibility of a continuous processing plant. An application has been demonstrated for a multipurpose plant with uncertain operating conditions. A practical flexibility analysis procedure using a direct search optimization algorithm is proposed to solve the problem. The method provides a heuristic screening technique that makes it possible to avoid the exhaustive enumeration of every constraint vertex, while the direct search optimization offers a simple and effective means to identify bottlenecks. A refinery multiperiod plant problem has been investigated in order to highlight the procedures which lead to the construction of flexibility indices for each operating mode. On a mis au point une methodologie pour l'analyse de la flexibilite operationnelle d'une unite de traitement continue. Une application est demontree pour une unite a usages multiples dans des conditions operatoires incertaines. Une procedure pratique d'analyse de la flexibilite utilisant un algorithme de recherche direct est proposee pour resoudre le probleme. La methode fournit une technique de selection heuristique qui permet d'eiter l'enumeration exhaustive de chaque sommet de contraintes, tandis que l'optimisation par recherche directe offre un moyen simple et efficace d'identifier les goulots d'etranglement. On a etudie une probleme pour une unite de raffinage a periodes multiples dans le but de mettre en evidence les procedures qui menent a l'etablissement des indices de flexibilite pour chaque mode operatoire.

A compact dual-wideband bandpass filter using an asymmetrical resonator is presented. The proposed resonator consists of three uniform microstrip lines of different lengths, and provides not only three transmission poles but also two transmission zeros for each passband. Thus, the bandpass filter has wide bandwidths and sharp cutoff responses. Theory as well as experimential results are given to validate this design concept.

A new zero-voltage switching (ZVS) converter with the series half-bridge legs for high DC bus application is presented. Two circuit modules with the interleaved pulse-width modulation are adopted to share the load current. In each circuit module, a series resonant converter with two transformers that are series-connected in primary side and parallel-connected in secondary side is used to achieve load current sharing and reduce the current stresses of rectified diodes and transformer secondary windings. Based on the series resonant behaviour, power metal-oxide semiconductor field-effect transistors (MOSFETs) are turned on at ZVS and rectifier diodes can be turned off at zero current switching. Therefore the switching losses of power semiconductors are reduced. Two half-bridge legs and two split capacitors are connected in series such that the voltage stress of each active switch is clamped to one-half of DC bus voltage. Thus, the low voltage stress of MOSFETs can be used in high DC bus application. The principle of operation, steady-state analysis and design consideration of the proposed converter are provided and discussed. Experiments with a laboratory prototype with 24 V/40 A output are provided to verify the effectiveness of the proposed converter.

An interleaved resonant converter for high voltage application is presented in this paper. There are two half-bridge legs connected in series and two split capacitors in the adopted circuit to limit the voltage stress of each active switch at one-half of input voltage. Thus MOSFETs with 600V voltage rating can be adopted for 1200V input voltage application. For each half-bridge leg, two series resonant circuits are operated with interleaved one-half of switching period. The secondary windings of two transformers are connected in series in order to balance the transformer primary currents and to share the input current. Thus the sizes of the transformer core and bobbin are reduced. The centre-tapped rectifier is used on the output side to reduce the conduction loss with one diode voltage drop. Based on the resonant behaviour, MOSFETs are turned on at ZVS, and rectifier diodes can be turned off at ZCS if the switching frequency is less than the series resonant frequency. Two half-bridge legs are operated with one-fourth of switching period such that the ripple currents at input and output sides arc reduced. Finally, experiments with a 960W prototype, verifying the effectiveness of the proposed converter, are described.

Cisapride is an orally administered prokinetic agent which facilitates or restores motility through the length of the gastrointestinal tract. It has been widely used in adult and ped, patients with reflux disease and functional dyspepsia. GER is often seen in premature infants with apnea or BPD, and cisapride is often prescribe in these infants. Because embryonic respiratory tract originates from foregut and shares the same innervation with gastrointestinal tract, it is very probable that cisapride may induce some tonic changes in airway smooth muscle. No study on this aspect has been done previously.

A technique is presented for recognizing a 3D object (a model in an image library) from a single 2D silhouette using information such as corners (points with high positive curvatures) and occluding contours, rather than straight line segments. The silhouette is assumed to be a parallel projection of the object. Each model is stored as a set of the principal quadtrees, from which the volume/surface octree of the model is generated. Feature points (i.e. corners) are extracted to guide the recognition process. Four-point correspondences between the 2D feature points of the observed object and 3D feature points of each model are hypothesized, and then verified by applying a variety of constraints to their associated viewing parameters. The result of the hypothesis and verification process is further validated by 2D contour matching. This approach allows for a method of handling both planar and curved objects in a uniform manner, and provides a solution to the recognition of multiple objects with occlusion as demonstrated by the experimental results. >

A technique involving sandwich-speckle interferometry has been investigated for application in making strain measurements on rotating structures. The technique has proven to be effective in relaxing stringent timing requirements for recording laser photographs and provides extended ranges of displacement measurement. Application of the technique to an experimental rotating specimen has demonstrated the potential of the method for making accurate strain measurements.

Octrees have been extensively used for 3D object representation. The authors have previously developed a scheme, that exploits the volume intersection approach, to generate the octree of an object from three orthogonal views. In this paper, the scheme is extended to generate a “generalized octree” of an object from three known non-coplanar views. The block associated with each node in a generalized octree is a parallelepiped, instead of being a cube. To identify an observed object, the generalized octree of the object is projected onto the corresponding principal planes and matched against a number of models, each of which is represented by a set of the quadtrees from three principal views. To speed up the processing, reconstruction of the structure of the object as well as computation of its moment of inertia matrix (comprising all the second-order moments) are performed in a generalized coordinate system specified by the three viewing directions. The coordinate transformation is applied only to the moment of inertia matrix. The principal axes are obtained from the transformed moment of inertia matrix by computing its eigenvectors. A “coarse” matching is performed by matching the quadtrees of the unknown object to those of the models, so as to extract a smaller set of models with strong similarity to the unknown object. The octrees of these models are then matched to that of the object using a “fine” matching process. The results of experiments conducted demonstrate that this approach makes both storage and computation highly efficient.

The octree structure for the representation of 3D objects is an extension of the quadtree representation of 2D (binary) images. It is generated from the 3D binary array of the object it represents. However, the acquisition of a 3D array is not a trivial problem. In this study, we propose a scheme to generate an octree of an object from its three orthogonal views (silhouettes) exploiting a volume intersection technique. A multi-level boundary search algorithm is developed to incorporate surface information into the octree representation. This makes the octree representation compact, informative, and especially useful for graphic displays and object recognition tasks. An algorithm is also designed for computing the moment of inertia matrix, which is useful for object recognition. All the algorithms developed in this study are essentially tree traversal procedures and therefore are suitable for implementation on parallel processors.

One hundred and fifteen cases of injection myopathy with deltoid and/or gluteal fibrotic contracture were studied, almost all of whom had definite histories of repeated intragluteal or intradeltoid injections. One third had siblings affected by the same fibro-muscular disorders manifestated by focal muscle atrophy and limitation of adduction and flexion of the shoulder or hip. Electromyography disclosed myopathic changes of the fibrotic muscles. Muscle biopsy showed marked perimysial and endomysial fibrosis with non-specific degeneration, regenerative changes and, in some cases, partial denervation signs. Under the electron microscope, endomysial and perimysial collagen fibrils lost their normal unimodal diameter distribution and showed a rather broad spectral distribution of diameters suggesting a defective control of collagen formation in this disease entity. Repeated injection injuries and myotoxicity resulting in multifocal myositis are the first trigger of this fibrotic syndrome, and abnormal control of collagen formation could be another important pathogenic factor.

In recent years, an important area of research in computer vision has been the recovery or inference of the 3-D information about a scene from its 2-D image. In light of the fascinating power of humans in inferring the 3-D structure of objects from visual images, a great deal of effort has been directed towards the understanding of each module in the human visual system. The results of these efforts have yielded mathematical models for most of these modules. In this chapter, we survey results of a variety of research work conducted in this area using different depth cues, including depth from stereopsis; structure from motion parallax and optical flow, shape from shading, texture, and surface contours; and shape from occluding contours. Also included are two nonanthropomorphic approaches, i.e., structure from volume intersection and shape from spatial encoding, which are closely tied to cues used in the human visual system for inferring 3-D structure from 2-D images. We present the strengths and shortcomings of each approach, and briefly discuss the possibility of combining different approaches in order to obtain more robust and reliable results, and suggest the direction of future research.

Matching historical performance of a reservoir is a time-consuming exercise with uncertain outcome. The current practice of manual matching is subjective and goodness of the match owes largely to the experiences of the team members involved in a study and to the quality and quantity of various input and observed data. This paper describes approaches taken to speed up the history matching effort during the course of replicating multiyear performance of two West African reservoirs. The study entails validation of production data, and matching of single-well and full-field performances with two automated-history-matching (AHM) approaches based on the Gauss-Newton algorithm. These finite-difference results obtained with AHM are contrasted with those obtained from the traditional manual approach. Results show that both AHM approaches shorten length of a study, and preserve objectivity of a history match. The use of grid coarsening results in impressive speed gain that can quickly provide clues whether adjustments of certain parameters are justified for some wells. That multiple parameter adjustments can be made within specified bounds with a few iterations in a 24-hour run is a profound improvement in our speed of learning of key reservoir flow behavior. This speed, in turn, guides the study in a path that leads to rapid conclusion in a fraction of time taken in a traditional study.