727 research outputs found
Lagrangian Relaxation for Mixed-Integer Linear Programming: Importance, Challenges, Recent Advancements, and Opportunities
Operations in areas of importance to society are frequently modeled as
Mixed-Integer Linear Programming (MILP) problems. While MILP problems suffer
from combinatorial complexity, Lagrangian Relaxation has been a beacon of hope
to resolve the associated difficulties through decomposition. Due to the
non-smooth nature of Lagrangian dual functions, the coordination aspect of the
method has posed serious challenges. This paper presents several significant
historical milestones (beginning with Polyak's pioneering work in 1967) toward
improving Lagrangian Relaxation coordination through improved optimization of
non-smooth functionals. Finally, this paper presents the most recent
developments in Lagrangian Relaxation for fast resolution of MILP problems. The
paper also briefly discusses the opportunities that Lagrangian Relaxation can
provide at this point in time
On the Influence of Corpuscular Fluxes and of Electron Photoloosening Reaction on the Formation of the D-Layer of the Ionosphere
Effect of corpuscular fluxes and electron photoloosening reaction on formation of ionospheric D laye
Quantitative Estimation of the Ratio of GABA-Immunoreactive Cells in Neocortical Grafts
Somatosensory anlage from 17-18 day old rat
embryos were transplanted in place of the
removed barrel cortex in adult rats. Six to eight
months after transplantation, the grafts were
either completely separated by glial scar or
partly separated and partly confluent with the
host neocortex. Each was studied histologically
and immunostained for GABA. It was found that
in partly confluent grafts the neuronal density
was similar or even higher than in the host
cortex, while the cell number in the separate
grafts was much lower than in the nearby host
cortex. The number of GABA-positive cells,
however, was in all grafts significantly lower
(2.9% on average) than in the normal cortex
(11.8% on average).The decline in GABA-stained
nerve cells was highest in separated
grafts, but was somewhat less marked in
transplants partly confluent with the host tissue.
The possible role of partial or total
deafferentation as well as the relative
vulnerability of the transplanted tissue by
temporary hypoxia and other metabolic
disturbances are discussed as the probable
factors in selective decline of GABA-ergic cells in
the transplanted somatosensory cortex
TO THE ISSUE HARDENING OF DRILLING EQUIPMENT PARTS
This paper considers the possibility of optimal hardened layer of parts operating in conditions of high abrasive wear. The experiments on obtaining of parts with a hardened layer, conducted their research of the macro and micro structure of the resulting coating thickness and wear resistance.Южно-Уральский государственный университет выражает благодарность за финансовую поддержку Министерства образования и науки Российской Федерации (грант № 11.9658.2017/БЧ)
Inspecting aviation composites at the stage of airplane manufacturing by applying 'classical' active thermal NDT, ultrasonic thermography and laser vibrometry
The results of applying three nondestructive testing techniques to the inspection of parts of a new Russian TVS-2DTS airplane made of carbon fiber reinforced plastic are presented. A basic technique implemented in workshop conditions implements optical stimulation of inspected parts. The usefulness of ultrasonic infrared thermography combined with laser vibrometry in the evaluation of parts with complicated geometry is illustrated. Samples with artificial and real defects have been tested in workshop conditions
Surrogate Lagrangian Relaxation: A Path To Retrain-free Deep Neural Network Pruning
Network pruning is a widely used technique to reduce computation cost and
model size for deep neural networks. However, the typical three-stage pipeline
significantly increases the overall training time. In this paper, we develop a
systematic weight-pruning optimization approach based on Surrogate Lagrangian
relaxation, which is tailored to overcome difficulties caused by the discrete
nature of the weight-pruning problem. We prove that our method ensures fast
convergence of the model compression problem, and the convergence of the SLR is
accelerated by using quadratic penalties. Model parameters obtained by SLR
during the training phase are much closer to their optimal values as compared
to those obtained by other state-of-the-art methods. We evaluate our method on
image classification tasks using CIFAR-10 and ImageNet with state-of-the-art
MLP-Mixer, Swin Transformer, and VGG-16, ResNet-18, ResNet-50 and ResNet-110,
MobileNetV2. We also evaluate object detection and segmentation tasks on COCO,
KITTI benchmark, and TuSimple lane detection dataset using a variety of models.
Experimental results demonstrate that our SLR-based weight-pruning optimization
approach achieves a higher compression rate than state-of-the-art methods under
the same accuracy requirement and also can achieve higher accuracy under the
same compression rate requirement. Under classification tasks, our SLR approach
converges to the desired accuracy faster on both of the datasets.
Under object detection and segmentation tasks, SLR also converges
faster to the desired accuracy. Further, our SLR achieves high model accuracy
even at the hard-pruning stage without retraining, which reduces the
traditional three-stage pruning into a two-stage process. Given a limited
budget of retraining epochs, our approach quickly recovers the model's
accuracy.Comment: arXiv admin note: text overlap with arXiv:2012.1007
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