18,265 research outputs found
Regression Depth and Center Points
We show that, for any set of n points in d dimensions, there exists a
hyperplane with regression depth at least ceiling(n/(d+1)). as had been
conjectured by Rousseeuw and Hubert. Dually, for any arrangement of n
hyperplanes in d dimensions there exists a point that cannot escape to infinity
without crossing at least ceiling(n/(d+1)) hyperplanes. We also apply our
approach to related questions on the existence of partitions of the data into
subsets such that a common plane has nonzero regression depth in each subset,
and to the computational complexity of regression depth problems.Comment: 14 pages, 3 figure
Benefits of demand-side response in providing frequency response service in the future GB power system
The demand for ancillary service is expected to increase significantly in the future Great Britain (GB) electricity system due to high penetration of wind. In particular, the need for frequency response, required to deal with sudden frequency drops following a loss of generator, will increase because of the limited inertia capability of wind plants. This paper quantifies the requirements for primary frequency response and analyses the benefits of frequency response provision from demand-side response (DSR). The results show dramatic changes in frequency response requirements driven by high penetration of wind. Case studies carried out by using an advanced stochastic generation scheduling model suggest that the provision of frequency response from DSR could greatly reduce the system operation cost, wind curtailment, and carbon emissions in the future GB system characterized by high penetration of wind. Furthermore, the results demonstrate that the benefit of DSR shows significant diurnal and seasonal variation, whereas an even more rapid (instant) delivery of frequency response from DSR could provide significant additional value. Our studies also indicate that the competing technologies to DSR, namely battery storage, and more flexible generation could potentially reduce its value by up to 35%, still leaving significant room to deploy DSR as frequency response provider
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Internet Pharmacies: Regulatory Problems and Potential Solutions
This paper will analyze the growing problem “rogue†Internet pharmacies—Internet pharmacies that conduct illegal or unsafe prescribing and dispensing practices that endanger the health of the customers they serve. SECTION I will describe the different categories of Internet pharmacies and distinguish the practice of legitimate Internet pharmacies from those of rogue Internet pharmacies. SECTION II will discuss the dangers customers face by ordering from rogue Internet pharmacies. SECTION III will address the currently regulatory regime for domestic Internet pharmacies. SECTION IV will address the currently regulatory regime for foreign Internet pharmacies. Finally, SECTION V will analyze recent proposals to more effectively curtail the illegal practice of domestic and foreign Internet pharmacies
Effect of Harvest Time on Seed Composition, Keeping Quality and Germination of Groundnut (Arachis Hypogaea L.) Var. Matjam
Differences in seed maturity during harvest have been a
conmon problem in groundnut. The present study was conducted
to look into different factors in order to obtain viable
information that could define optimum harvest for Mat jam
groundnut. These characters include: (a) percentage of nature
pods per 100 pads, (b) weight of kernels per plant, (c) oil,
protein, and carbohydrate contents, (d) keeping quality, and
(e) germination rate.
The groundnut was grown in the field in 1986 and 1987 and
harvested at 17 different harvest dates from 68 days after
planting (DAP) to 100 DAP.
The percentage of mature pods per 100 pods in both years
was about 65.6% at 88 DAP. Later harvests did not show
significant increase in percentage of mature pods. Highest
kernel weight of 8.18 g/plant was obtained at 100 DAP but was
not significantly different from the 92 and 96 DAP with 7.78
am 6.55 g/plant, respectively. The number of nodes on the
main axis between 88-96 DAP ranged from 26 to 28. This plant
character was easy to identify and to count because even when
the leaves had fallen, the scars could still be seen
Simple ultraviolet-based soft-lithography process for fabrication of low-loss polymer polysiloxanes-based waveguides
A simple ultraviolet (UV)-based soft-lithography process is used for fabrication of polymer polysiloxanes (PSQ-L) waveguides. The imprint process is first done on the cladding PSQ-LL layer and is followed by a spin-coating step to fill the imprinted features with core PSQ-LH layer material. The optical loss of the straight PSQ-L waveguides is characterised by the Fabry-Perot method for the first time. Even with non-polished facet of the waveguide, the Fabry-Perot resonance spectrum is obtained. An upper limit scattering loss of the waveguide is extracted to be less than 0.8 +/- 0.2 dB/cm for TE mode and 1.3 +/- 0.2 dB/cm for TM mode at 1550 nm. The fully transferred pattern and low scattering loss proves it to be an effective way to replicate low-loss polymer PSQ-L-based waveguides
Constrained structure of ancient Chinese poetry facilitates speech content grouping
Ancient Chinese poetry is constituted by structured language that deviates from ordinary language usage [1, 2]; its poetic genres impose unique combinatory constraints on linguistic elements [3]. How does the constrained poetic structure facilitate speech segmentation when common linguistic [4, 5, 6, 7, 8] and statistical cues [5, 9] are unreliable to listeners in poems? We generated artificial Jueju, which arguably has the most constrained structure in ancient Chinese poetry, and presented each poem twice as an isochronous sequence of syllables to native Mandarin speakers while conducting magnetoencephalography (MEG) recording. We found that listeners deployed their prior knowledge of Jueju to build the line structure and to establish the conceptual flow of Jueju. Unprecedentedly, we found a phase precession phenomenon indicating predictive processes of speech segmentation—the neural phase advanced faster after listeners acquired knowledge of incoming speech. The statistical co-occurrence of monosyllabic words in Jueju negatively correlated with speech segmentation, which provides an alternative perspective on how statistical cues facilitate speech segmentation. Our findings suggest that constrained poetic structures serve as a temporal map for listeners to group speech contents and to predict incoming speech signals. Listeners can parse speech streams by using not only grammatical and statistical cues but also their prior knowledge of the form of language
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