Dimensionality Reduction for k-Means Clustering and Low Rank Approximation

We show how to approximate a data matrix $\mathbf{A}$ with a much smaller sketch $\mathbf{\tilde A}$ that can be used to solve a general class of constrained k-rank approximation problems to within $(1+\epsilon)$ error. Importantly, this class of problems includes $k$-means clustering and unconstrained low rank approximation (i.e. principal component analysis). By reducing data points to just $O(k)$ dimensions, our methods generically accelerate any exact, approximate, or heuristic algorithm for these ubiquitous problems. For $k$-means dimensionality reduction, we provide $(1+\epsilon)$ relative error results for many common sketching techniques, including random row projection, column selection, and approximate SVD. For approximate principal component analysis, we give a simple alternative to known algorithms that has applications in the streaming setting. Additionally, we extend recent work on column-based matrix reconstruction, giving column subsets that not only `cover' a good subspace for \bv{A}, but can be used directly to compute this subspace. Finally, for $k$-means clustering, we show how to achieve a $(9+\epsilon)$ approximation by Johnson-Lindenstrauss projecting data points to just $O(\log k/\epsilon^2)$ dimensions. This gives the first result that leverages the specific structure of $k$-means to achieve dimension independent of input size and sublinear in $k$

Socio-economic impact of photovoltaic park: The Giurgiu County rural area, Romania

The paper aims to analyse the socio-economic territorial impact of photovoltaic parks in the rural area of Giurgiu County. The analysis valorises two types of data: the statistical information on the local socio-economic features provided by the National Institute of Statistics and the Giurgiu County Statistics Office, and the specific information about the photovoltaic parks revealed by the interviews applied to the local authorities during field investigation. The case-studies discussed in this paper reflect the socio-economic effects of building and operating the six photovoltaic parks as in the three rural local administrative units – LAU2: Izvoarele, Stăneşti and Malu. This study emphasizes four types of the socio-economic effects of investment in a photovoltaic project on: local rural economy, land use changes, local investments, budget and local labour market

CONSIDERATIONS ON THE PROTECTION OF VINEYARDS AND ORCHARDS AGAINST HOAR AND FROST

No matter how favourable the light and humidity conditions may be, plant growth stops when the air and leaf temperature drops below a certain minimum or exceeds a certain maximum value. When air temperatures drop below 0 °C, susceptible crops can be injured, with significant effects on production. Hoar and late frosts occur differently, there are areas where the number of days in the spring months with critical temperature drops are quite numerous, with a frequency in April and exceptionally during May. The negative effect is all the greater as it is recorded after a warm period which can cause an advance of the period of formation of flower buds and the appearance of flowers. The paper presents a series of considerations on the protection of orchards and vineyards against hoar and late frosts

Spontaneous coronary artery dissections and fibromuscular dysplasia: Current insights on pathophysiology, sex and gender

International audienc

ADVANTAGES ON THE USE OF INDUSTRY 4.0 IN THE FIELD OF AGRICULTURE

Recently, studies show that the world is at the beginning of a new era of the industrial revolution, representing the fourth industrial revolution known as Industry 4.0. This will have an impact on research, technologies, manufacturing processes and people by connecting many products to the Internet, the presence of sensors, the expansion of wireless communications, the development of industrial robots and intelligent machines, the analysis of real-time data in order to transform how the research is conducted. The present paper presents the advantages of implementing Industry 4.0 in the field of agriculture

RESEARCHES ON THE PROTECTION OF VINEYARDS AND ORCHARDS AGAINST SPRING FROSTS USING HEAT AND SMOKE AND USING THE RESULTING ASH AS SOIL AMENDMENT

Orchards and vineyards can be exposed to climatic phenomena with unfavorable effects on tree growth and fruiting, such as: winter frosts, frosts and late spring frosts, hail, icing, etc. Smoke and heat are a valuable ally of fruit and vine growers, often intervening in preventing and limiting the negative effects of frosts and frosts on fruit trees and vines during the periods of budding, flowering and fruit binding. The accident is due to the freezing of water in the cellular structure of the vegetative organs (flower buds, buds, flowers, leaves). The paper presents a method of the protection for orchards and vineyards against hoar and late frosts as well as the possibility to use the resulting ash as soil amendment

RESEARCHES ON THE DEVELOPMENT OF AN EXPERIMENTAL MODEL OF WET SATURATED STEAM DISTILLATION EQUIPMENT

Distillation is a conventional method of extracting volatile oils from medicinal and aromatic plants. This is defined as a process of separating the components of a mixture that is based on the difference between the vaporization temperatures of the constituents, respectively water and oil when distilling medicinal plants. Distillation can be performed in three ways: distillation with water, by boiling the mixture of plants and water, condensation of resulting vapours and separation of oil, distillation with water and steam, in which the steam obtained by evaporating a quantity of water passes through the plant batch; steam distillation under pressure provided by an external generator, a process named in the literature and steam entrainment. The steam distillation process is applicable to many medicinal and aromatic plants that grow in our country. The extraction of volatile oils through this process depends on the different characteristics of the plants but also on the main parameters of the process, pressure and temperature, which are different

L'adhésion thérapeutique dans l'hypertension artérielle résistante

peer reviewe

Management of a pregnant woman with fibromuscular dysplasia

No abstract available

INFLUENCE ON QUALITY AND ENERGY INDICES FOR A REVERSIBLE PLOW EQUIPPED WITH ELECTRIC VIBRATORS

The qualitative indices of the tillage as well as the exploitation energy indices represent two relevant factors in the exploitation of the agricultural equipments, these being the main barometer of the quality of the used equipment. The paper presents a comparative study of qualitative work indices, respectively energy indices, performed on two reversible plows with three troops, one used in the classical system and one optimized by implementing electrical systems for generating vibrations, located on each of the three active troops during operatio