Low-rank SIFT: An Affine Invariant Feature for Place Recognition

In this paper, we present a novel affine-invariant feature based on SIFT, leveraging the regular appearance of man-made objects. The feature achieves full affine invariance without needing to simulate over affine parameter space. Low-rank SIFT, as we name the feature, is based on our observation that local tilt, which are caused by changes of camera axis orientation, could be normalized by converting local patches to standard low-rank forms. Rotation, translation and scaling invariance could be achieved in ways similar to SIFT. As an extension of SIFT, our method seeks to add prior to solve the ill-posed affine parameter estimation problem and normalizes them directly, and is applicable to objects with regular structures. Furthermore, owing to recent breakthrough in convex optimization, such parameter could be computed efficiently. We will demonstrate its effectiveness in place recognition as our major application. As extra contributions, we also describe our pipeline of constructing geotagged building database from the ground up, as well as an efficient scheme for automatic feature selection

The Relationship Between Social Phobia, Peer Attachment, And Identity Within Different Cultural Contexts

This study investigated the relationship between social phobia, peer attachment, and identity development, within three different countries: China, India, and the USA. It was hypothesized that social phobia interferes with peer attachment, and that poor peer attachment interferes with identity development among late adolescents and emerging adults, thus peer attachment mediates the relationship between social phobia and identity. It was further hypothesized that this relationship between variables is moderated by culture such that in collectivistic cultures, where identity is more dependent upon group affiliation and identification, the interference of social phobia (through peer attachment) on identity would be much greater than in individualistic cultures where identity may be based more on unique characteristics. Participants were 422 undergraduate students from three locations: China (n = 180), India (n = 96), and the USA (n = 146). Results varied by country. For the combined sample collectivism, social phobia, and peer attachment each independently predicted identity. Collectivism also negatively predicted social phobia and positively predicted peer attachment. None of the variables served as a mediator or moderator between the other variables. In the USA sample, collectivism predicted identity but was mediated by peer attachment. Social phobia negatively predicted peer attachment and identity, but was not related to collectivism. In the Chinese sample, peer attachment predicted identity, but was mediated by social phobia. Collectivism predicted identity, but was not related to the other two variables. Among the Indian sample none of the variables predicted identity. A number of possible reasons for these complex results are explored

Objective and subjective assessment of perceptual factors in HDR content processing

The development of the display and camera technology makes high dynamic range (HDR) image become more and more popular. High dynamic range image give us pleasant image which has more details that makes high dynamic range image has good quality. This paper shows us the some important techniques in HDR images. And it also presents the work the author did. The paper is formed of three parts. The first part is an introduction of HDR image. From this part we can know why HDR image has good quality

AGENT-BASED DISCRETE EVENT SIMULATION MODELING AND EVOLUTIONARY REAL-TIME DECISION MAKING FOR LARGE-SCALE SYSTEMS

Computer simulations are routines programmed to imitate detailed system operations. They are utilized to evaluate system performance and/or predict future behaviors under certain settings. In complex cases where system operations cannot be formulated explicitly by analytical models, simulations become the dominant mode of analysis as they can model systems without relying on unrealistic or limiting assumptions and represent actual systems more faithfully. Two main streams exist in current simulation research and practice: discrete event simulation and agent-based simulation. This dissertation facilitates the marriage of the two. By integrating the agent-based modeling concepts into the discrete event simulation framework, we can take advantage of and eliminate the disadvantages of both methods.Although simulation can represent complex systems realistically, it is a descriptive tool without the capability of making decisions. However, it can be complemented by incorporating optimization routines. The most challenging problem is that large-scale simulation models normally take a considerable amount of computer time to execute so that the number of solution evaluations needed by most optimization algorithms is not feasible within a reasonable time frame. This research develops a highly efficient evolutionary simulation-based decision making procedure which can be applied in real-time management situations. It basically divides the entire process time horizon into a series of small time intervals and operates simulation optimization algorithms for those small intervals separately and iteratively. This method improves computational tractability by decomposing long simulation runs; it also enhances system dynamics by incorporating changing information/data as the event unfolds. With respect to simulation optimization, this procedure solves efficient analytical models which can approximate the simulation and guide the search procedure to approach near optimality quickly.The methods of agent-based discrete event simulation modeling and evolutionary simulation-based decision making developed in this dissertation are implemented to solve a set of disaster response planning problems. This research also investigates a unique approach to validating low-probability, high-impact simulation systems based on a concrete example problem. The experimental results demonstrate the feasibility and effectiveness of our model compared to other existing systems

Packaging Design of IGBT Power Module Using Novel Switching Cells

Parasitic inductance in power modules generates voltage spikes and current ringing during switching which cause extra stress in power electronic devices, increase electromagnetic interference (EMI), and degrade the performance of the power converter system. As newer power devices have faster switching speeds and higher power ratings, the effect of the parasitic inductance of the power module is more pronounced. This dissertation proposes a novel packaging method for power electronics modules based on the concepts of novel switching cells: P-cell and N-cell. It can reduce the stray inductance in the current commutation path in a phase-leg module and hence improve the switching behavior. Taking an insulated gate bipolar transistor (IGBT) as an example, two phase-leg modules, specifically a conventional module and a P-cell and N-cell based module were designed. Using Ansoft Q3D Extractor, electromagnetic simulation was carried out to extract the stray inductance from the two modules. An ABB 1200 V / 75 A IGBT model and a diode model were built for simulation study. Circuit parasitics were extracted and modeled. Switching behavior with different package parasitics was studied based on the Saber simulation. Two prototype phase-leg modules were fabricated. The parasitics were measured using a precision impedance analyzer. The measurement results agree with the simulation very well. A double pulse tester was built in laboratory. Several approaches were used to reduce the circuit and measuring parasitics. From the switching characteristics of the two modules, it was verified that the larger stray inductance in the layout causes higher voltage overshoot during turn off, which in turn increases the turn off losses. Multichip (two in parallel) IGBT modules applying novel switching cells was also designed. The parasitics were extracted and compared to a conventional design. The overall loop inductance was reduced in the proposed module. However, the mismatch of the paralleled branches was larger

The Role Of Ferric Oxide Particles As Sources And Sinks Of Reactive Oxygen Species During The Autoxidation Of Ferrous Iron

The oxic portion of the biosphere is a metastable mixture of different oxidation states of carbon, sulfur and oxygen energetically poised from equilibrium by the net rate differentials between photosynthetic carbon fixation and its metabolic or abiotic oxidation. The direct reaction of dioxygen with reduced carbon or sulfur is spin forbidden and therefore kinetically slow, but ferric and ferrous iron species serve as catalysts for enabling their oxidation and therefore play critical roles in the environment. This thesis reports exploratory and hypothesis driven research that seeks a better understanding of the physical and chemical limitations on the effectiveness of iron to catalyze interaction between the different oxidation states of these elements. These include studies of the relationship between iron speciation and its ability to generate reactive oxygen species (Chapter 1); the role of heterogeneous iron oxide suspensions in controlling reactive oxygen species yield during the spontaneous reaction of Fe(II) and O2 (Chapter 2), an exploration of the system of natural iron-containing soils, sulfide and oxygen and how they produce superoxide and hydrogen peroxide (Chapter 3) and a preliminary report of reactive oxygen species and antioxidant enzyme formation in the salt marsh muds (Chapter 4). The results are showing that ferric iron catalyzed oxidation of hydrogen sulfide is an important reservoir for the generation of reactive oxygen species except for the photoinduced processes. The ferrous iron oxidation in the presence of ferric oxides shows a faster oxidation rate and produces a higher yield of reactive oxygen species, which is indicating the catalysis of the process by removing ferric species from the iron cycle

Incorporation of Arbitration Clauses under a Charterparty and a Bill of Lading: English and Chinese Law Perspectives

In commercial maritime law, "the contract of affreightment" and "marine insurance" may be the most important and difficult subjects. As far as the contract of affreightment is concerned, the difficulites derive from the existence of two entirely different forms of contracts, a charterparty and a bill of lading. In order to explore commercial maritime law, one key question is to research the interrelationship between the charterparty and the bill of lading. The object of this thesis is to examine the interrelationship between a charterparty and a bill of lading under the contract of affreightment, particularly, the incorporation of the arbitration clause under the charterparty and the bill of lading, because the charterparty is linked with the bill through incorporation clauses