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1.
Papaioannou G. Karabassi E.-A. Theoharis T. 《IEEE transactions on pattern analysis and machine intelligence》2002,24(1):114-124
The problem of re-assembling an object from its parts or fragments has never been addressed with a unified computational approach, which depends on the pure geometric form of the parts and not on application-specific features. We propose a method for the automatic reconstruction of a model based on the geometry of its parts, which may be computer-generated models or range-scanned models. The matching process can benefit from any other external constraint imposed by the specific application 相似文献
2.
Lighting design is an essential process in computer cinematography, games, architectural design and various other applications for correctly illuminating or highlighting parts of a scene and enhancing storytelling. When targeting specific illumination goals and constraints, this process can be tedious and counter-intuitive even for experienced users and thus automatic, goal-driven methods have emerged for the estimation of a lighting configuration to match the desired result. We present a general automatic approach to such an inverse lighting design problem, where the number of light sources along with their position and emittance are computed given a set of user-specified lighting goals. To this end, we employ a special hierarchical light clustering that operates in the lighting goal coverage domain and overcomes limitations of previous approaches in environments with high occlusion or structural complexity. Our approach is independent of the underlying light transport model and can quickly converge to usable solutions. We validate our results and provide comparative evaluation with the current state of the art. 相似文献
3.
Mobile code has been championed as a solution to a plethora of software problems. This paper describes investigative work undertaken in order to evaluate the mobile code abstractions of Mobile Agents and Mobile Objects, and to understand the implications of using these abstractions to build distributed systems.We describe two systems built to support the Sales Order Process of a distributed manufacturing enterprise, using IBM's Aglets Software Development Kit. The Sales Order Process model and the requirements for agility used as the basis for these implementations are derived from data collected in an industrial case study.Both systems are evaluated using the Goal/Question/Metric methodology. Two new metrics for Semantic Alignment and Change Capability are presented and used to evaluate each system with respect to the degree of system agility supported. The systems are evaluated through a set of scenarios generated during the case study in an attempt to see if they support system integration and agility in the manufacturing domain. Further we examine the implications of using a mobile code abstraction when compared with the abstraction offered by traditional distribution technology.The work described provides evidence that both Mobile Agent and Mobile Object systems have inherent properties that can be used to build agile distributed systems. Further, Mobile Agents with their additional autonomy provide marginally greater support. 相似文献
4.
In this paper we consider communication issues arising in cellular (mobile) networks that utilize frequency division multiplexing
(FDM) technology. In such networks, many users within the same geographical region can communicate simultaneously with other
users of the network using distinct frequencies. The spectrum of available frequencies is limited; thus, efficient solutions
to the frequency-allocation and the call-control problems are essential. In the frequency-allocation problem, given users
that wish to communicate, the objective is to minimize the required spectrum of frequencies so that communication can be established
without signal interference. The objective of the call-control problem is, given a spectrum of available frequencies and users
that wish to communicate, to maximize the number of users served. We consider cellular, planar, and arbitrary network topologies.
In particular, we study the on-line version of both problems using competitive analysis. For frequency allocation in cellular
networks, we improve the best known competitive ratio upper bound of 3 achieved by the folklore Fixed Allocation algorithm, by presenting an almost tight competitive analysis for the greedy algorithm;
we prove that its competitive ratio is between 2.429 and 2.5 . For the call-control problem, we present the first randomized algorithm that beats the deterministic lower bound of 3 achieving a competitive ratio between 2.469 and 2.651 for cellular networks. Our analysis has interesting extensions to arbitrary networks. Also, using Yao's Minimax Principle,
we prove two lower bounds of 1.857 and 2.086 on the competitive ratio of randomized call-control algorithms for cellular and arbitrary planar networks, respectively. 相似文献
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The present report gives an insight into the specific changes in the three main carotenoids (lycopene, γ-carotene and β-carotene) occurring in Blakeslea trispora cultures, with regard to medium composition. Various carbon sources and refined natural vegetable oils as co-substrates were used. The different carbon sources greatly affect the final composition of carotenoids, with lactose medium to preferentially accumulate the all-trans-β-carotene. Furthermore, the use of lactose and starch as carbon sources, respectively, gives a first indication that B. trispora is able to metabolise various homo- and hetero-saccharides, thus leading to different carotenoid percentages. The presence of oils as co-substrates resulted in enhanced fungus growth and subsequent higher carotenoid production. Substrates containing linoleic acid or other oils rich in it led to less lycopene accumulation. The data showed that the biosynthesis of lycopene, γ-carotene and β-carotene starts in most cases simultaneously in the early growth phase even in trace amounts and thus may play a role also as antioxidants for the B. trispora cells. 相似文献
9.
Marsh Herbert W.; Papaioannou Athanasios; Theodorakis Yannis 《Canadian Metallurgical Quarterly》2006,25(3):316
Does prior physical self-concept influence subsequent exercise behavior? On the basis of a large sample of physical education classes (2,786 students, 200 classes, 67 teachers) collected early (Time 1) and late (Time 2) in the school year, findings support a reciprocal effects model in which prior physical self-concept and exercise behavior both influence subsequent physical self-concept and exercise behavior. Whereas variables from the theory of planned behavior (TOPB; behavioral intentions, perceived behavioral control, exercise attitudes) also contributed to the prediction of subsequent exercise behavior, the effect of prior physical self-concept was significant for subsequent outcomes after controlling these variables, suggesting that the TOPB should be supplemented with self-concept measures. On the basis of multilevel models, there were systematic differences in these variables for students taught by different teachers that generalized over time and across different classes taught by the same teacher. Support for the reciprocal effects model was robust. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
BA Evans M Papaioannou F Anastasopoulos RJ Summers 《Canadian Metallurgical Quarterly》1998,124(4):763-771
Stimulation of alpha-adrenoceptors on ventricular cardiomyocytes isolated from adult rat hearts leads to cellular alkalization, increases of creatine phosphate concentration, RNA mass, and protein synthesis. This study investigated whether the increase of creatine phosphate concentrations is causally linked to the hypertrophic response of cardiomyocytes under alpha-adrenoceptor stimulation. Cellular alkalization achieved with phenylephrine (10 microM), an alpha-adrenoceptor agonist, was abolished in the presence of the sodium-proton-exchange (NHE)-inhibitor HOE 694 (1 microM). HOE 694 inhibited also the alpha-adrenoceptor-mediated increase in cellular creatine phosphate and the increase in cellular RNA mass. The phenylephrine-induced stimulation of protein synthesis (determined by incorporation of 14C-phenylalanine) was reduced by one-third when HOE 694 was present. beta-Guanidinopropionic acid was added to cardiomyocytes to reduce cellular creatine phosphate concentrations. In these cultures, alpha-adrenoceptor stimulation activated NHE, but creatine phosphate concentrations were not increased. Protein synthesis was augmented to the same extent as in control cultures, but total RNA mass did not increase. From these results we conclude that alpha-adrenoceptor stimulation causes the increase in protein synthesis via activation of NHE, but independent of the concomitant increase in creatine phosphate contents. The effect of alpha-adrenoceptor stimulation on total RNA mass (translational capacity) is also caused by NHE activation, but depends on the changes in creatine phosphate contents as well. 相似文献