scholarly journals Clustering heuristic for time-dependent periodic routing problems with complex constraints

2021 ◽  
Vol 14 (2) ◽  
Author(s):  
Tomasz Śliwiński
Keyword(s):  
Large Scale ◽  
Optimization Problems ◽  
Solution Concept ◽  
Objective Evaluation ◽  
Routing And Scheduling ◽  
Long Term Stability ◽  
Personnel Allocation ◽  
The Given ◽  
Periodic Routing

Periodic routing and scheduling is of utmost importance in many industries with mobile personnel working in the field: sales representatives, service technicians, suppliers, etc. The resulting optimization problems are of large scale and complexity, mostly due to discrete, combinatorial nature of the systems and due to complicated, nonuniform constraints. In many cases the long-term stability of the customer to personnel allocation is required, leading to the decomposition of the major problem into single employee subproblems.The paper deals with building clusters of customers visited by a single salesperson. The procedure takes into account diverse system requirements and constraints, possible traveling schedules and expected operational costs. The difficulty of the problem lies in its large scale and constraints complexity as well as in troublesome objective evaluation for the given solution. The general solution concept is presented. Its usefulness is supported by the results of the computational experiments.

scholarly journals A survey of short-term and long-term stability of tube parameters in a mammography unit

2014 ◽  
Vol 29 (4) ◽  
pp. 321-325
Author(s):  
Jovica Praskalo ◽  
Jasna Davidovic ◽  
Biljana Kocic ◽  
Monika Zivkovic ◽  
Svetlana Pejovic
Keyword(s):  
Screening Program ◽  
Short Term ◽  
X Ray ◽  
Term Stability ◽  
Long Term Stability ◽  
Mammography Screening Program ◽  
The Republic ◽  
Set Up ◽  
The Given

In order to set up a successful mammography screening program in the Republic of Srpska, a Siemens Mammomat 1000 X-ray machine was selected for analysis as the said mammography system is widely used in clinical practice. The variations in tube parameters (specific air kerma, high-voltage accuracy and reproducibility, linearity between exposure and dose exposure time) were monitored over a five-year period, from 2008 to 2012. In addition, due to observed daily fluctuations for chosen parameters, a series of measurements were performed three times a day within a single-month period (mainly October 2012). The goal of such an experimental set up is to assess short-term and long-term stability of tube parameters in the given mammography unit and to make a comparison between them. The present paper shows how an early detection of significant parameter fluctuations can help eliminate irregularities and optimize the performance of mammography systems.

scholarly journals A Modified Conjugacy Condition and Related Nonlinear Conjugate Gradient Method

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Shengwei Yao ◽  
Xiwen Lu ◽  
Bin Qin
Keyword(s):  
Conjugate Gradient Method ◽  
Conjugate Gradient ◽  
Gradient Method ◽  
Large Scale ◽  
Optimization Problems ◽  
Special Role ◽  
Conjugacy Condition ◽  
Nonlinear Conjugate Gradient Method ◽  
Nonlinear Conjugate Gradient ◽  
The Given

The conjugate gradient (CG) method has played a special role in solving large-scale nonlinear optimization problems due to the simplicity of their very low memory requirements. In this paper, we propose a new conjugacy condition which is similar to Dai-Liao (2001). Based on this condition, the related nonlinear conjugate gradient method is given. With some mild conditions, the given method is globally convergent under the strong Wolfe-Powell line search for general functions. The numerical experiments show that the proposed method is very robust and efficient.

scholarly journals Effect of Sodium Salicylate on the Viscoelastic Properties and Stability of Polyacrylate-Based Hydrogels for Medical Applications

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Zuzana Kolarova Raskova ◽  
Martina Hrabalikova ◽  
Vladimir Sedlarik
Keyword(s):  
Sodium Salicylate ◽  
Antimicrobial Properties ◽  
Processing Conditions ◽  
Bacterial Strains ◽  
Noticeable Effect ◽  
Term Stability ◽  
Long Term Stability ◽  
One Year ◽  
The Given

Investigation was made into the effect exerted by the presence of sodium salicylate (0–2 wt.%), in Carbomer-based hydrogel systems, on processing conditions, rheological and antimicrobial properties in tests against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacterial strains, and examples of yeast (Candida albicans) and mould (Aspergillus niger). In addition, the work presents an examination of long-term stability by means of aging over one year the given hydrogels at 8°C and 25°C. The results show that 0.5 wt.% NaSal demonstrated a noticeable effect on the hydrogel neutralization process, viscosity, and antimicrobial properties against all of the tested microorganisms. The long-term stability studies revealed that hydrogels can maintain antimicrobial activity as well as viscosity to a degree that would be sufficient for practical use.

scholarly journals 24h urinary free cortisol in large-scale epidemiological studies: Short-term and long-term stability and sources of variability

2014 ◽  
Vol 47 ◽  
pp. 10-16 ◽  
Author(s):  
Judith G.M. Rosmalen ◽  
Ido P. Kema ◽  
Stefan Wüst ◽  
Claude van der Ley ◽  
Sipke T. Visser ◽  
...  
Keyword(s):  
Large Scale ◽  
Urinary Free Cortisol ◽  
Epidemiological Studies ◽  
Short Term ◽  
Term Stability ◽  
Long Term Stability ◽  
Free Cortisol

scholarly journals Highly scalable multichannel mesh electronics for stable chronic brain electrophysiology

2017 ◽  
Vol 114 (47) ◽  
pp. E10046-E10055 ◽  
Author(s):  
Tian-Ming Fu ◽  
Guosong Hong ◽  
Robert D. Viveros ◽  
Tao Zhou ◽  
Charles M. Lieber
Keyword(s):  
Large Scale ◽  
Single Neuron ◽  
Neurological Diseases ◽  
Field Potential ◽  
Brain Regions ◽  
Long Term Stability ◽  
High Density Recording ◽  
Local Circuits ◽  
Key Aspects

Implantable electrical probes have led to advances in neuroscience, brain−machine interfaces, and treatment of neurological diseases, yet they remain limited in several key aspects. Ideally, an electrical probe should be capable of recording from large numbers of neurons across multiple local circuits and, importantly, allow stable tracking of the evolution of these neurons over the entire course of study. Silicon probes based on microfabrication can yield large-scale, high-density recording but face challenges of chronic gliosis and instability due to mechanical and structural mismatch with the brain. Ultraflexible mesh electronics, on the other hand, have demonstrated negligible chronic immune response and stable long-term brain monitoring at single-neuron level, although, to date, it has been limited to 16 channels. Here, we present a scalable scheme for highly multiplexed mesh electronics probes to bridge the gap between scalability and flexibility, where 32 to 128 channels per probe were implemented while the crucial brain-like structure and mechanics were maintained. Combining this mesh design with multisite injection, we demonstrate stable 128-channel local field potential and single-unit recordings from multiple brain regions in awake restrained mice over 4 mo. In addition, the newly integrated mesh is used to validate stable chronic recordings in freely behaving mice. This scalable scheme for mesh electronics together with demonstrated long-term stability represent important progress toward the realization of ideal implantable electrical probes allowing for mapping and tracking single-neuron level circuit changes associated with learning, aging, and neurodegenerative diseases.

Research of High Performance Artificial Reef for Breeding Abalone in Sea Water

2006 ◽  
Vol 302-303 ◽  
pp. 398-404
Author(s):  
Ming Tang ◽  
Xiao Li ◽  
Tao Wang
Keyword(s):  
High Performance ◽  
Large Scale ◽  
Sea Water ◽  
Artificial Reef ◽  
Silicon Powder ◽  
Ocean Current ◽  
Concrete Technology ◽  
Long Term Stability ◽  
One Year

According to abalone’s growth characteristics, artificial abalone reefs are invented in this paper. The trace elements are added in concrete. The proportion is fixed by test. Ocean alga adheres to reefs with them very well. The craft, matching optimization, curing terms in the island environment and concrete long-term stability in the ocean current are studied to solve the durability of reefs in the marine environment. It shows the durability of fishing reef by high performance, high function, and ecological concrete technology is reliable. Its strength is still increasing for one year and no damage has been found. It is feasible to use the complex admixture, high-quality fly ash, ultrafine silicon powder, surface-soaking-into water-hating material made by our own, adhering-shaking-compact molding equipment made by ourselves and solar-energy-curing technology. Ten thousands of large-scale artificial abalone reefs have been done. A large amount of marine organisms covered the reefs only after 40 days using.

Management options for increasing the productivity of tropical savanna pastures. IV. Population biology of introduced Stylosanthes spp

1989 ◽  
Vol 40 (6) ◽  
pp. 1227 ◽  
Author(s):  
JJ Mott ◽  
WH Winter ◽  
RW McLean
Keyword(s):  
Population Biology ◽  
Large Scale ◽  
Rapid Decline ◽  
Management Options ◽  
Hard Seed ◽  
Long Term Stability ◽  
Stylosanthes Humilis ◽  
Townsville Stylo ◽  
Fertilizer Rates

In a large-scale grazing experiment in the Monsoon Tallgrass savannas of the Northern Territory, Townsville stylo (Stylosanthes humilis), Caribbean stylo (S. hamata) and perennial stylo (S. scabra + S. viscosa) were sown into native pasture and grazed at three stocking rates, under two fertilizer rates and with trees killed and unkilled. These treatments, together with the occurrence of anthracnose, led to the rapid decline in both yield and numbers of plants in those pastures sown to Townsville stylo. In contrast, yields of Caribbean stylo and Perennial stylo stabilized after three years in both fertilized and unfertilized swards. While total legume yield of these latter two treatments was similar, the dominant contribution in Caribbean stylo was made by annual plants, while in Perennial stylo swards individuals more than 18 months old contributed 80% of the yield.There were marked differences between all species in their population biology. Townsville stylo declined in numbers with death of individuals prior to seed set and the rapid depletion of the soil seed pool which had little long-lived seed. In contrast, in swards of Caribbean stylo a large amount of hard seed rapidly built up in the soil seed pool and ensured continuity of productivity even if seed was not set in some years. In the perennial stylos, seed softened quickly, and the soil seed pool remained small and short-lived. In these latter Stylosanthes spp., long-term stability depended on the survival of perennating plants rather than seed.Pasture management must take into account these different patterns of population dynamics. In particular, while fire is a potentially useful tool in renovating Caribbean stylo swards with their large soil seed pool, it can be extremely detrimental to perennial stylo swards where individuals are susceptible to burning and there is little soil seed available to re-establish the sward.

Cooperation Strategies in Mongolian Pastoralism During the Socialist Collective Economy

Inner Asia ◽  
2005 ◽  
Vol 7 (2) ◽  
pp. 193-214
Author(s):  
Christian Ressel
Keyword(s):  
Environmental Conditions ◽  
Large Scale ◽  
State Policies ◽  
Climatic Changes ◽  
Socialist Society ◽  
Economic Action ◽  
Socialist State ◽  
The Given ◽  
Seasonal Climatic Changes

AbstractMy analysis of cooperation strategies considers pastoralism in the context of its long-term relationship to the steppe environment, geographical conditions and seasonal climatic changes. Under the influence of socialist state policies, previous socio–economic patterns were superseded by a ‘progressive’ re-organisation of production that created a new frame for economic action. The resultant forms of cooperation, as implemented by herders, related to different modes of production, which D. Sneath describes as ‘specialist’ and ‘domestic’ modes. During the collective period these modes largely correlated with different concepts of animal property.Within large–scale collective farms communal production became central to herders’ activities. Specialist production was carried out with collective-owned animals according to new formal structures, whereas the management of limited private herds was largely unaffected by official regulations and continued to be organised informally. Correspondingly, different cooperation strategies among herders’ groups were implemented in accordance with different kinds of social obligations and interests, each being adjusted adequately to the given socio-economic and environmental conditions. The differences between concepts of socialist society and the way herders acted in practice to some degree enabled the accumulation of larger private herds and facilitated the continuation of ‘old’ pre-collective patterns under ‘new’ socialist conditions.

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