Common Manifold Research Articles

Full-space local topology extraction for cross-modal retrieval.

With the ever increasing availability of various kinds of multimedia data, cross-modal retrieval, which enables information retrieval from various types of data given various types of query, has become a research hotspot. Hashing-based techniques have been developed to solve this problem, however, most previous works cannot capture the shared underlying structure of real-world multimodal data, which degrades their retrieval performances. In this paper, we propose a novel hashing method based on the extraction of the common manifold structure shared among different feature spaces. To faithfully represent the common structure, two kinds of local topology information are exploited in our method. Local angles are incorporated within the extraction of local topology of each feature space, which is then used to learn a common intermediate subspace. After heterogeneous features being embedded into this subspace, local similarities are exploited to extract the local topology between different feature spaces, and learn compact Hamming embeddings to facilitate cross-modal retrieval. The proposed method is referred to as full-space local topology extraction for hashing. Extensive comparisons with other state-of-the-art methods on three benchmark multimedia data sets demonstrate the superiority of our proposed method in terms of retrieval recall and search accuracy.

Novel carbocationic rearrangements of 1-styrylpropargyl alcohols.

The dehydration and subsequent cyclization reactions of 1-styrylpropargyl alcohols was examined. In the course of these studies, numerous scaffolds were synthesized, including a furan, a cyclopentenone, an acyclic enone and even a naphthalenone. The diversity of these structural motifs lies in novel cascades of reactions originating from a common carbocationic manifold.

“Distributed hybrid” MH–CGH2 system for hydrogen storage and its supply to LT PEMFC power modules

This paper describes the layout and presents the results of the testing of a novel prototype “distributed hybrid” hydrogen storage and supply system that has the potential to be used for Low Temperature Proton Exchange Membrane Fuel Cell (LT-PEMFC) applications. The system consists of individual Metal Hydride (MH) and Compressed Gas (CGH2) tanks with common gas manifold, and a thermal management system where heat exchanger of the liquid heated-cooled MH tank is integrated with the cooling system of the LT-PEMFC BoP. The MH tank is filled with a medium-stability AB2-type MH material (H2 equilibrium pressure of about 10bar at room temperature). This innovative solution allows for (i) an increase in hydrogen storage capacity of the whole gas storage system and the reduction of H2 charge pressure; (ii) shorter charging times in the refuelling mode and smoother peaks of H2 consumption during its supply to the fuel cell stack; (iii) the use of standard parts with simple layout and lower costs; and (iv) adding flexibility in the layout and placement of the components of the hydrogen storage and supply system.

Orbit Approach to Separation of Variables in $${\mathfrak{sl}}$$ sl (3)-Related Integrable Systems

Using the orbit method we attempt to reveal geometric and algebraic meaning of separation of variables for the integrable systems on coadjoint orbits in an $\mathfrak{sl}(3)$ loop algebra. We consider two types of generic orbits embedded into a common manifold, endowed with two nonsingular Lie-Poisson brackets. We prove that separation of variables on orbits of both types is realized by the same variables of separation. We also construct the integrable systems on these orbits: a coupled 3-component nonlinear Schr\"{o}dinger equation and an isotropic SU(3) Landau-Lifshitz equation.

Wide‐angle scanning active transmit/receive reflectarray

A highly integrated phased array transmit/receive architecture is presented. Multilayer microstrip antennas with a scanning potential up to 60° are combined, on a common manifold, with SiGe MMICs including four RF channels each, together with the necessary digital control circuits. Power distribution and combining are realised by the concept of a folded planar reflectarray. This study also includes the necessary solutions for multilayer interconnects and efficient heat removal from the active circuits. To prove the concept, passive arrays with different fixed beam positions have been tested successfully; followed by a first active array demonstrating excellent scanning performance up to 60° both in E- and H-plane.

ANALYSIS AND CONTROL OF FACIAL EXPRESSIONS USING DECOMPOSABLE NONLINEAR GENERATIVE MODELS

Facial expressions convey personal characteristics and subtle emotional states. This paper presents a new framework for modeling subtle facial motions of different people with different types of expressions from high-resolution facial expression tracking data to synthesize new stylized subtle facial expressions. A conceptual facial motion manifold is used for a unified representation of facial motion dynamics from three-dimensional (3D) high-resolution facial motions as well as from two-dimensional (2D) low-resolution facial motions. Variant subtle facial motions in different people with different expressions are modeled by nonlinear mappings from the embedded conceptual manifold to input facial motions using empirical kernel maps. We represent facial expressions by a factorized nonlinear generative model, which decomposes expression style factors and expression type factors from different people with multiple expressions. We also provide a mechanism to control the high-resolution facial motion model from low-resolution facial video sequence tracking and analysis. Using the decomposable generative model with a common motion manifold embedding, we can estimate parameters to control 3D high resolution facial expressions from 2D tracking results, which allows performance-driven control of high-resolution facial expressions.

Analytical Approach Determining the Optimal Length of Paired Drip Laterals in Uniformly Sloped Fields

Microirrigation plants, if properly designed, allow for water use efficiency to be optimized and high values of emission uniformity to be obtained in the field. Disposing paired laterals, for which two distribution pipes extend in opposite directions from a common manifold, can contribute to reducing the initial investment cost that represents a limiting factor for small-scale farmers of developing countries where in the last decade, the diffusion of such irrigation systems has been increasing. The objective of this paper is to propose an analytical approach to evaluate the maximum lengths of paired drip laterals for any uniform ground slope, respecting the criteria to maintain emitter flow rates or the corresponding pressure heads within fixed ranges in order to achieve a relatively high field emission uniformity coefficient. The method is developed by considering the motion equations along uphill and downhill sides of the lateral and the hypothesis to neglect the variations of emitters’ flow rate along the lateral as well as the local losses due to emitters’ insertions. If for the uphill pipe, the minimum and the maximum pressure heads occur at the upstream end and at the manifold connection, respectively, on the downhill side, the minimum pressure head is located in a certain section of the lateral, depending on the geometric and hydraulic characteristics of the lateral, as well as on the slope of the field; a second relative maximum pressure head could also exist at the downstream end of the pipe. The proposed methodology allows in particular the number of emitters in uphill and downhill sides of the lateral to be determined separately, and therefore, once fixing emitter’s spacing, the length of the uphill and downhill laterals and the position of the manifold. Applications and validation of the proposed approach, considering different design parameters, are finally presented and discussed.

Manifold aligned ground motion prediction equations for regional datasets

Inferring a ground-motion prediction equation (GMPE) for a region in which only a small number of seismic events has been observed is a challenging task. A response to this data scarcity is to utilise data from other regions in the hope that there exist common patterns in the generation of ground motion that can contribute to the development of a GMPE for the region in question. This is not an unreasonable course of action since we expect regional GMPEs to be related to each other. In this work we model this relatedness by assuming that the regional GMPEs occupy a common low-dimensional manifold in the space of all possible GMPEs. As a consequence, the GMPEs are fitted in a joint manner and not independent of each other, borrowing predictive strength from each other׳s regional datasets. Experimentation on a real dataset shows that the manifold assumption displays better predictive performance over fitting regional GMPEs independent of each other.

The intellectual task of musicologists in the building of a European citizenship

This paper, which has been proposed as keynote speech at the study session “Transmission of musical knowledge: constructing a European citizenship” (Rome, XIX IMS conference, July 6, 2012), suggests that it is important, and useful (in terms of both education and politics) for all citizens of the European Union, and for the foreigners who access the EU, to highlight the art music ( Kunstmusik , musica d’arte ) heritage, which constitutes one of the peculiar, distinctive features of European culture, and whose importance cannot certainly be reduced to the sphere of entertainment. The art music heritage raises specific issues, first of all its composite nature. We have a material heritage, made of objects that require preservation (instruments, scores, treatises, documents, buildings designed for music performance); and we have an immaterial heritage – whose value can be aesthetic (works and events, i.e. music pieces to be performed or listened to) or intellectual (music texts, writings on music, theoretical and practical knowledge, performance techniques). The latter can only survive if it is taken care of and transmitted. Knowledge of the European music heritage can be a powerful tool for integration in the building of a European citizenship, since it makes us aware that we have one common musical tradition, open and manifold. This provides a shared reference framework to the many local musical traditions scattered over the continent, and, at the same time, offers a reading key (by analogy and/or contrast) to groups of non-European citizens who come from different music cultures and aim at integrating into the Union. In this process, musicologists can play a crucial role, if only they understand that one of the missions of their discipline is to educate and transmit musical culture. Music pedagogy and didactics are not separate fields - on the contrary, we must again look at them as a supporting branch, vigorous and thriving, attached to the trunk of musicology. Restoring this status should be primarily the task of musicologists.

Semi-Supervised Affine Alignment of Manifolds

High dimensional data is usually produced by the source that only enjoys a limited number of degrees of freedom. Manifold leaning technique plays an important part in finding the correlation among the high dimensional data datasets. By making use of manifold alignment, the paired mapping relationship can be explored easily. However, the common manifold alignment algorithm can only give the mapping result of the training set, and cannot deal with a new coming point. A new manifold alignment algorithm is proposed in this paper. The benefit of our algorithm is two fold: First, the method is a semi-supervised approach, which makes better use of the local geometry information of the unpaired points and improves the learning effect when the labeled proportion is very low. Second, an extended spectral aggression trick is used in the algorithm, which can produce a linear mapping between the raw data space and the aligned space. The experiments result shows that, the correlation mapping can be precisely obtained, the hidden space can be aligned effectively, and the cost of mapping a coming point is very low. DOI : http://dx.doi.org/10.11591/telkomnika.v12i4.4808

AdS5with two boundaries and holography ofN=4SYM theory

According to the AdS/CFT correspondence, the ${\cal N}=4$ supersymmetric Yang-Mills (SYM) theory is studied through its gravity dual whose configuration has two boundaries at the opposite sides of the fifth coordinate. At these boundaries, in general, the four dimensional (4D) metrics are different, then we expect different properties for the theory living in two boundaries. It is studied how these two different properties of the theory are obtained from a common 5D bulk manifold in terms of the holographic method. We could show in our case that the two theories on the different boundaries are described by the Ad$S_5$, which is separated into two regions by a domain wall. This domain wall is given by a special point of the fifth coordinate. Some issues of the entanglement entropy related to this bulk configuration are also discussed.

TWO-PHASE COOLING OF CONCENTRATING PHOTOVOLTAIC CELLS

Experimental investigation of a heat sink for cooling of photovoltaic solar cells up to 2000 suns concentration was conducted. Flow boiling of refrigerant HFC-134a in a pin-fin microchannel was investigated in the range of mass flux 220–380 kg/m 2 s, heat flux 30–170 W/cm 2 , and an exit vapor quality, xout, from 0.2 to 0.75. The heat sink was a pin-fin microchannel module installed in an open flow loop. Deviation from the measured area average temperatures was 1.5 ◦ C at q = 30 W/cm 2 , and 2.0 ◦ C at q = 170 W/cm 2 . These results indicate that use of pin-fin microchannel heat sink enables keeping an electronic device near uniform temperature under steady state and transient conditions. The heat transfer coefficient varied significantly with refrigerant quality and showed a peak at an exit vapor quality of 0.55 in all the experiments. At relatively low heat fluxes and vapor qualities, the heat transfer coefficient increased with vapor quality. At high heat fluxes and vapor qualities, the heat transfer coefficient decreased with vapor quality. Solar cells are more expensive than traditional crystalline silicon; the total cell area needed to provide a specified power level can be reduced, due to their inherently higher efficiency and the use of concentration, thus minimizing solar cell material cost. It is expected that concentrating photovoltaics (CPV), in which the large area of expensive semiconductors is replaced with an equivalent area of relatively low-cost optical reflectors, will lead to considerable cost savings. The power density per unit area of the cell is greatly enhanced by collecting and focusing the light into a small intense beam leading to a reduced cell footprint for comparable power generation. Parabolic or circular paraboloid dish concentrators work by reflecting all incoming light incident on its surface to a single focal point, where the receiver containing the cells is located. Parabolic dishes can be scaled up or down in size and have a theoretical concentration limit of 10,000 suns. This factor is lower in practice due to imperfections in the reflecting surface, but 2000 suns or more is attainable. Solar cells, like most semiconductor-based electronic devices, are adversely affected by temperature. When the temperature rises, more electrons are excited into the conduction band and, in a PV cell, this has the effect of reducing power conversion efficiency. Concentrator photovoltaic systems, or CPVs, are used to gather solar energy by using reflective surfaces to concentrate solar light onto a small photovoltaic cell. This reduces the cost of energy production because the materials for the reflective surfaces are cheaper than solar cells. The problem with this method, however, is that the high concentration of sunlight heats up the solar cells to high temperatures very quickly and consequently may decrease the efficiency of the electricity production. Also, nonuniform temperature distribution on the heated surface may result in potentially destructive thermal stresses along the interface between the chip and the substrate or heat sink. This is one of the key justifications for seeking nearly isothermal heat sinks. Furthermore, a large temperature gradient is undesirable for the electronic performance since many electronic parameters are adversely affected by a substantial temperature rise (Workman et al., 1998; Bohr, 1995). Two-phase flow in parallel microchannels, for which the feed is from a common manifold, displays interesting phenomena, as the two phases may split unevenly when entering the parallel piping. A nonuniform distribution of a

A general approach for synchronisation of nonlinear networked systems with switching topology

This article investigates synchronisation of a nonlinear networked system with switching topology. By defining a common synchronisation manifold for each possible switching topology, exponential synchronisation of a nonlinear networked system can be assessed by the exponential stability of a reduced nonlinear system corresponding to the concerned system, wherein the communication graph can be directed and weighted and the inner-linking matrix might be singular. In particular, a synchronisation criterion consisting of the self-dynamics of isolated nodes and the consensus dynamics of a linear switched system is given. Two numerical simulations of synchronisation are presented to illustrate the effectiveness of the analytical results for the periodic and random switching cases.

Design and Optimization of a Compact Superconducting Quadruplexer at VHF-Band With an Accurate Equivalent Circuit Model

This paper presents the modeling and optimization of a manifold-coupled superconducting quadruplexer at VHF-band. The quadruplexer consists of four individually designed channel filters with a bandwidth of 400 kHz centered at 216, 224, 232, and 240 MHz, respectively, connected to a common manifold. The complex interactions between the channel filters make the design and optimization of the quadruplexer difficult and even impossible. An equivalent circuit for the manifold and the capacitive external couplings of the four channel filters in the quadruplexer is presented. The parameters of the equivalent circuit are accurately extracted from electromagnetic simulations. Afterward, the equivalent circuit is optimized to compensate for the interactions between the channel filters and obtain a good common-port return loss and channel transfer characteristics. Thereafter, the design of the individual channel filters is improved according to the optimized parameters of the equivalent circuit. The superconducting quadruplexer is successfully designed and fabricated. The measurements show high performance and match well with the simulations. The experimental insertion losses of the four channels are less than 0.45 dB, the center frequency discrepancies of the four channels are less than 40 kHz, the common-port return loss is greater than 16.3 dB, and the out-of-band rejection is higher than 90 dB. Moreover, a high isolation greater than 75 dB between the channels is achieved.

Hexagonal reciprocating pump: advantages and weaknesses

This paper reports the 1-D fluid transient simulation results of the discharge flow conditions in a 6-cylinder reciprocating slurry pump. Two discharge manifold configurations are studied comparatively; a case with a hexagon shaped discharge manifold where each cylinder discharges at a single vertex, and a case where all the cylinders discharges are lumped together into a tank shaped manifold. In addition, the study examines the effect of two pulsation mitigation measures in the case of hexagonal manifold; a single inline orifice in one of the hexagon sides and a volumetric dampener at the manifold outlet. The study establishes the pressure and flow fluctuation characteristics of each configuration and decouples the pulsation characteristics of the pump and the discharge manifold. 1. Summary Reciprocating pumps produce flow variations in their discharge end that may excite severe pressure pulsation in their discharge manifolds and piping systems. Therefore, developing of new designs of such pumps or introduction of novel configurations of discharge manifold warn an investigation of their flow dynamic characteristics and their susceptibility to acoustic and mechanical resonance. Numerical transient flow simulation is an effective front-end engineering measure to assess the susceptibility to detrimental pulsation flow acoustic performance. This paper reports the simulation results of the discharge flow conditions in a 6-cylinder hexagon shaped reciprocating slurry pump (Hexagonal pump). Two discharge manifold configurations of the same pump are studied comparatively; a case with a hexagon shaped discharge manifold where each cylinder discharges at a single vertex, and a case where all the cylinders discharges are lumped together into a tank shaped manifold. The study establishes the discharge pressure fluctuation characteristics of each configuration, quantifies the flow and pressure pulsation, and decouples the pulsation characteristics of the pump and the discharge manifold. In addition, the study examines the effect of two pulsation mitigation measures in the case of hexagonal pump with hexagonal manifold; a single inline orifice in one of the hexagon sides and a volumetric dampener at the manifold outlet. Finally, it compares the discharge pulsation characteristics of a reciprocating hexagonal pump with those of similar capacity triplex pumps conventionally used in oil wells drilling and in the mining industry. A one-dimensional transient flow simulator is used to investigate the pumping hydrodynamic of a slightly-compressible homogeneous slurry flow. The Hexagonal pump analyzed is based on an emerging industrial product design where the vertical reciprocating motion of the pistons is driven by a rotating cam, and where the kinematic of the piston motion is carefully configured, by the cam profile, to smooth the compound pump discharge flow/pressure. The simulation results of the common discharge tank case show that, under realistic conditions of delays in valves actions, severe discharge pulsation occurs. This pressure pulsation is in the same level of severity as in the crankshaft driven triplex pump used conventionally in drilling oil and gas wells. Furthermore, the simulations of the hexagonal manifold revealed that a complex alternating flow condition prevails in the six sides of the hexagons in response to the six reciprocating pistons actions. Simulation results suggest that the Hexagonal manifold provides certain level of damping when compared with the case of discharging to a common tank manifold. However, it generates multiple high energy frequency spikes over a wide frequency range, some of them at the high frequency range, with tendencies to excite the piping system and the mechanical frame of the pump.

Global generalized synchronization in networks of different time-delay systems

We show that global generalized synchronization (GS) exists in structurally different time-delay systems, even with different orders, with quite different fractal (Kaplan-Yorke) dimensions, which emerges via partial GS in symmetrically coupled regular networks. We find that there exists a smooth transformation in such systems, which maps them to a common GS manifold as corroborated by their maximal transverse Lyapunov exponent. In addition, an analytical stability condition using the Krasvoskii-Lyapunov theory is deduced. This phenomenon of GS in strongly distinct systems opens a new way for an effective control of pathological synchronous activity by means of extremely small perturbations to appropriate variables in the synchronization manifold.

Fast Time Resolution Oxidized Mercury Measurements during the Reno Atmospheric Mercury Intercomparison Experiment (RAMIX)

The Reno Atmospheric Mercury Intercomparison Experiment (RAMIX) was carried out from 22 August to 16 September, 2011 in Reno, NV to evaluate the performance of new and existing methods to measure atmospheric mercury (Hg). Measurements were made using a common sampling manifold to which controlled concentrations of Hg species, including gaseous elemental mercury (GEM) and HgBr2 (a surrogate gaseous oxidized mercury (GOM) compound), and potential interferents were added. We present an analysis of Hg measurements made using the University of Washington's Detector for Oxidized Hg Species (DOHGS), focusing on tests of GEM and HgBr2 spike recovery, the potential for interference from ozone (O3) and water vapor (WV), and temporal variability of ambient reactive mercury (RM). The mean GEM and HgBr2 spike recoveries measured with the DOHGS were 95% and 66%, respectively. The DOHGS responded linearly to HgBr2. We found no evidence that elevated O3 interfered in the DOHGS RM measurements. A reduction in RM collection and retention efficiencies at very high ambient WV mixing ratios is possible. Comparisons between the DOHGS and participating Hg instruments demonstrate good agreement for GEM and large discrepancies for RM. The results suggest that existing GOM measurements are biased low.

Do We Understand What the Mercury Speciation Instruments Are Actually Measuring? Results of RAMIX

From August 22 to September 16, 2012, atmospheric mercury (Hg) was measured from a common manifold in the field during the Reno Atmospheric Mercury Intercomparison eXperiment. Data were collected using Tekran systems, laser induced fluorescence, and evolving new methods. The latter included the University of Washington-Detector for Oxidized Mercury, the University of Houston Mercury instrument, and a filter-based system under development by the University of Nevada-Reno. Good transmission of total Hg was found for the manifold. However, despite application of standard protocols and rigorous quality control, systematic differences in operationally defined forms of Hg were measured by the sampling systems. Concentrations of reactive Hg (RM) measured with new methods were at times 2-to-3-fold higher than that measured by Tekran system. The low RM recovery by the latter can be attributed to lack of collection as the system is currently configured. Concentrations measured by all instruments were influenced by their sampling location in-the-manifold and the instrument analytical configuration. On the basis of collective assessment of the data, we hypothesize that reactions forming RM were occurring in the manifold. Results provide a new framework for improved understanding of the atmospheric chemistry of Hg.

Feature matching based on unsupervised manifold alignment

Feature-based methods for image registration frequently encounter the correspondence problem. In this paper, we formulate feature-based image registration as a manifold alignment problem, and present a novel matching method for finding the correspondences among different images containing the same object. Different from the semi-supervised manifold alignment, our methods map the data sets to the underlying common manifold without using correspondence information. An iterative multiplicative updating algorithm is proposed to optimize the objective, and its convergence is guaranteed theoretically. The proposed approach has been tested for matching accuracy, and robustness to outliers. Its performance on synthetic and real images is compared with the state-of-the-art reference algorithms.

A Three-Dimensional Parametric Study and Numerical/Experimental Flow Visualization of a Six-Pocket Hydrostatic Journal Bearing

This article presents a numerical investigation and some experimental results supporting evidence on the flow structure and the pressure distribution in a hydrostatic journal bearing with six equidistant pockets. The parametric studies are of both operational and geometric nature. The operational ones include shaft's angular speed and inlet pressure. The geometric ones include pocket depth, eccentricity, clearance and restrictor diameter. The latter two are instrumental in changing the ratio of the restrictor to clearance hydraulic resistance (R). The flow regime in the bearing is kept in the laminar range (Rebrg < 60). It was found that for the deep pocket the pressure is uniformly distributed across its circumferential length, whereas for the shallow pocket it increases in a ramp fashion along the direction of rotation. The oil injected through the restrictor forms a penetrating jet that constitutes the driver of the upstream and downstream vortical cells that eventually interact with the Couette effect generated by the rotating shaft. This latter effect deforms both the upstream and downstream vortical cells, causing the downstream one to elongate and occupy a large portion of the pocket center. A direct consequence is the formation of a central vortical cell located at the mouth of the restrictor. It has become evident that the flow in the restrictor has to be modeled when simulating the flow in the pockets, because it represents an influential boundary condition that significantly alters the structure of the flow in the pocket itself. A novel modeling feature is the introduction of large sink-type reservoirs upstream of the restrictors. This allows prescription of the same pressure at the inlet of these ‘sinks’, thus simulating a common and constant pressure manifold for all restrictors. For high speeds of rotation the pressure on the lands between the pockets is dominated by hydrodynamic effects, which cause pressures higher than the hydrostatic pressure in the convergent zone. This situation has important consequences on the overall flow structure in pockets adjacent to these large hydrodynamic pressures, as the flow may be completely shut off at the circumferential and partially at the axial exits of the pocket. The change in the resistance R is associated with the change in the hydrodynamic to hydrostatic pressure component dominance in the bearing. Some validating qualitative experimental results concerning the numerical simulation of the flow in the pockets and associated feed mass flows are also presented.