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排序方式: 共有264条查询结果,搜索用时 46 毫秒
71.
This paper considers a dynamic lot sizing problem faced by a producer who supplies a single product to multiple customers. Characterized by their backorder costs as well as shipping costs, a customer with a high backorder cost has a greater need for the product than a customer with a low backorder cost. We show that the general problem with time-varying customer-dependent backlogging and shipping costs is NP-hard in the strong sense. We then develop an efficient dynamic programming algorithm for an important instance of the problem when there is no speculative motive for backlogging. We also establish forecast horizon results for the case of stationary production and shipping costs, which help the decision maker determine a proper forecast horizon in a rolling-horizon planning process. 相似文献
72.
This paper is concerned with the problem of production planning in a flexible manufacturing system consisting of a single or parallel failure-prone machines producing a number of different products. The objective is to choose the rates of production of the various products over time in order to meet their demands at the minimum long-run average cost of production and surplus. The analysis proceeds with a study of the corresponding problem with a discounted cost. It is shown using the vanishing discount approach for the average cost problem that the Hamilton-Jacobi-Bellman equation in terms of directional derivatives has a solution consisting of the minimal average cost and the so-called potential function. The result helps in establishing a verification theorem, and in specifying an optimal control policy in terms of the potential function. The results settle a hitherto open problem as well as generalize known results. 相似文献
73.
This paper addresses the problem of direct image and video manipulation in compressed domain. The capability to perform such
manipulations has become attractive in recent years, as more and more visual information is being captured, stored, and moved
in compressed form. Our solution to direct manipulation of compressed images and video is based on a set of block-level transforms,
called the inner block transforms (IBTs). Each IBT requires a minimal computation effort in compressed domain to yield a regular geometric transformation on
an image block. The paper shows how the IBTs can be used to perform many image and video manipulations. This is done by describing
the application of IBTs to image subtitling, shearing, and arbitrary angle rotation. The paper also discusses the application
of IBT to M-JPEG and MPEG video. The benefits of the proposed direct compressed domain manipulation approach include faster
speed, preservation of image quality, and less computing resources. 相似文献
74.
Probe Station Placement for Robust Monitoring of Networks 总被引:1,自引:0,他引:1
We address the problem of selecting probe station locations from where probes can be sent to monitor all the nodes in the
network. Probe station placement involves instrumentation overhead. Hence, the number of probe stations should be minimal
to reduce the deployment cost. Also, probe station placement should be such that the network can be monitored even in the
presence of failures. We present algorithms to select locations of probe stations so that the entire network can be monitored
for computing various performance metrics. We aim to find a minimal set of probe station nodes so as to minimize the instrumentation
overhead. The algorithm presented provides robust monitoring in presence of node failures. We then present algorithms to make
the solution resilient to probe station failures, and to deal with weakly connected nodes. We provide an experimental evaluation
of the proposed algorithms through simulation results.
相似文献
Adarshpal S. SethiEmail: |
75.
Zhang D Tai LK Wong LL Putti TC Sethi SK Teh M Koay ES 《Proteomics. Clinical applications》2008,2(1):99-107
The human epidermal growth factor receptor type 2 (HER‐2/neu) oncoprotein is overexpressed in about 30% of breast cancers and associates with metastatic phenotypes of breast tumours. Dissecting the HER‐2/neu‐modulated molecules in cancer will be helpful in elucidating the underlying molecular mechanisms of HER‐2/neu‐driven tumourigenesis. We investigated the differential proteome profiles between microdissected HER‐2/neu‐positive and ‐negative tumours and unambiguously identified 21 proteins with diverse biological functions by peptide sequencing and NCBInr database interrogation. Six proteins were up‐regulated whereas 15 were down‐regulated in the HER‐2/neu‐positive tumours. Differential expressions of heterogeneous nuclear ribonucleoprotein H1 (hnRNP H1), 78 kDa glucose‐regulated protein (GRP78/Bip) and Raf‐1 kinase inhibitor protein (RKIP), which have not been previously reported as being linked to HER‐2/neu signalling, were further verified. Immunohistochemical staining on tissue microarray sections demonstrated a positive correlation of hnRNP H1 (p = 0.008) and negative correlations of GRP78 and RKIP (p = 0.018 and 0.013, respectively) with HER‐2/neu. Heregulin α1 enhanced hnRNP H1, but reduced GRP78 and RKIP expression in BT474 cells in a dose‐dependent manner, providing evidence of crosstalk between HER‐2/neu signalling and these modulators. Our studies have identified novel modulators that are likely to be intricately involved in HER‐2/neu‐driven tumour proliferation, invasion and metastasis. 相似文献
76.
Furukawa Y Sethi A Ponce J Kriegman DJ 《IEEE transactions on pattern analysis and machine intelligence》2006,28(2):302-315
This paper addresses the problem of estimating the motion of a camera as it observes the outline (or apparent contour) of a solid bounded by a smooth surface in successive image frames. In this context, the surface points that project onto the outline of an object depend on the viewpoint and the only true correspondences between two outlines of the same object are the projections of frontier points where the viewing rays intersect in the tangent plane of the surface. In turn, the epipolar geometry is easily estimated once these correspondences have been identified. Given the apparent contours detected in an image sequence, a robust procedure based on RANSAC and a voting strategy is proposed to simultaneously estimate the camera configurations and a consistent set of frontier point projections by enforcing the redundancy of multiview epipolar geometry. The proposed approach is, in principle, applicable to orthographic, weak-perspective, and affine projection models. Experiments with nine real image sequences are presented for the orthographic projection case, including a quantitative comparison with the ground-truth data for the six data sets for which the latter information is available. Sample visual hulls have been computed from all image sequences for qualitative evaluation. 相似文献
77.
T. Sethi A. Chaturvedi R. K. Upadhyaya S. P. Mathur 《Protection of Metals and Physical Chemistry of Surfaces》2009,45(4):466-471
The effect of Schiff’s bases alone and Schiff’s bases with additive Na2SO4 on the corrosion of aluminium in H2SO4 have been investigated by using weight loss method. The present study revealed that aluminium in H2SO4 has been more efficiently inhibited by Schiff’s bases in the presence of additive Na2SO4 than Schiff’s bases alone due to the synergistic effect between Schiff’s bases and Na2SO4. Inhibition efficiency was found maximum upto 95.02% for aluminium in H2SO4 by Schiff’s bases in presence of additive NaNa2SO4. The adsorption of inhibitor accords with the Langmuir adsorption isotherm. Results obtained in both the cases indicate the
dependence of inhibition efficiencies on the concentration of Schiff’s bases, additive Na2SO4 and also on the concentration of H2SO4 solution. The results show the increasing trends of inhibition efficiency with the concentration.
The article is published in the original. 相似文献
78.
The selective intermacromolecular complex formation between p-bromophenol-formaldehyde copolymer (PPF) and poly(vinyl pyrrolidone) (PVP) and poly(ethylene oxide) (PEO) has been investigated. PVP has been found to have greater ability for complex formation compared to PEO with respect to PPF. An open-chain mechanism has been proposed for the substitution reaction between PVP and PPF-PEO complex. The abnormal behaviour of viscosity curves has been interpreted on the basis of probable association between the nonionic polymers. 相似文献
79.
Chemically prepared amorphous Fe-Ni-B alloy particles 总被引:1,自引:0,他引:1
S. Mørup S. A. Sethi S. Linderoth C. Bender Koch M. D. Bentzon 《Journal of Materials Science》1992,27(11):3010-3013
Amorphous Fe-Ni-B alloy particles have been prepared by chemical reduction of Fe2+ and Ni2+ in aqueous solution by NaBH4. It was found that within a limited range of NaBH4 concentrations and pH values of the metal salt solution the particles are amorphous. Outside this range the precipitates are partly crystalline. The magnetic hyperfine fields of the amorphous particles, estimated from57Fe Mössbauer spectroscopy, are similar to those of amorphous ribbons with the same compositions. 相似文献
80.