检索结果-南通市图书馆

国际医学放射学杂志 2024年第4期 501-502页

作者： E.Demondion O.Ernst A.Louvet B.Robert g.kafri E.Langzam 常雪

摘要目的以MRI作为参考标准，在大型病人队列中评估通过双层探测器光谱CT(DL-CT)的三物质分离算法测量肝脏脂肪含量的可行性。方法回顾性纳入104例病人，每

关键词：

A Novel Approach to Probability

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Advances in Pure Mathematics 2016年第4期6卷 201-211页

作者： Oded kafri kafri Nihul Ltd. Tel Aviv Israel

When P indistinguishable balls are randomly distributed among L distinguishable boxes, and considering the dense system , our natural intuition tells us that the box with the average number of balls P/L has the highest probability and that none of boxes are empty;however in reality, the probability of the empty box is always the highest. This fact is with contradistinction to sparse system (i.e. energy distribution in gas) in which the average value has the highest probability. Here we show that when we postulate the requirement that all possible configurations of balls in the boxes have equal probabilities, a realistic “long tail” distribution is obtained. This formalism when applied for sparse systems converges to distributions in which the average is preferred. We calculate some of the distributions resulted from this postulate and obtain most of the known distributions in nature, namely: Zipf’s law, Benford’s law, particles energy distributions, and more. Further generalization of this novel approach yields not only much better predictions for elections, polls, market share distribution among competing companies and so forth, but also a compelling probabilistic explanation for Planck’s famous empirical finding that the energy of a photon is hv.

关键词： Probability Statistics Benford’s Law Zipf’s Law Planck’s Law Configurational Entropy

Zipf’s Law, Benford’s Law, and Pareto Rule

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Pure Mathematics 2023年第3期13卷 174-180页

作者： Oded kafri kafri Nihul Ltd. Tel Aviv Israel

From a basic probabilistic argumentation, the Zipfian distribution and Benford’s law are derived. It is argued that Zipf’s law fits to calculate the rank probabilities of identical indistinguishable objects and that Benford’s distribution fits to calculate the rank probabilities of distinguishable objects. i.e. in the distribution of words in long texts all the words in a given rank are identical, therefore, the rank distribution is Zipfian. In logarithmic tables, the objects with identical 1st digits are distinguishable as there are many different digits in the 2nd, 3rd… places, etc., and therefore the distribution is according to Benford’s law. Pareto 20 - 80 rule is shown to be an outcome of Benford’s distribution as when the number of ranks is about 10 the probability of 20% of the high probability ranks is equal to the probability of the rest of 80% low probability ranks. It is argued that all these distributions, including the central limit theorem, are outcomes of Planck’s law and are the result of the quantization of energy. This argumentation may be considered a physical origin of probability.

关键词： Zipf’s Law Benford’s Law Pareto 20 - 80 Rule Planck’s Law Max Entropy

Entropy and Temperature of Electromagnetic Radiation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Natural Science 2019年第12期11卷 323-335页

作者： Oded kafri kafri Nihul Ltd. Tel Aviv Israel

Electromagnetic (EM) radiation is both wave and heat. Waves are characterized by spectral distribution, spatial distribution, time coherence, spatial coherence, energy flux, and polarization. Heat, namely energy transferred from a hot body to a cold one, is characterized by its energy and entropy, and the ratio between them is the temperature. Here we calculate the entropy and temperature of a single radiation mode from the wave properties of the radiation. Using the Heisenberg uncertainty principle and Planck law, we calculate, from the optical properties of the radiation, the number of modes and their occupation number. Then we calculate the entropy and temperature of a single-mode EM radiation. It is shown that the entropy of a single-mode varies from zero for low occupation number, namely in the quantum limit to one Boltzmann constant for high occupation number, namely in the classical limit. The temperature varies from zero Kelvin in the quantum limit to infinity at high energies in the classical limit. This analysis is consistent with Fourier optics and statistical mechanics namely: Stephan-Boltzmann Law, Wein Law, Zipf law, IT File’s entropy, and the canonical distribution.

关键词： Thermodynamics Statistical Physics Optics Coherence

Follow the Multitude—A Thermodynamic Approach

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Natural Science 2014年第7期6卷 528-531页

作者： Oded kafri Varicom Communications Ltd. Tel Aviv Israel

When a bit is added to a file, its entropy increases by one nat regardless of the length of the file or the value of the bit. However, when a node is added to a network, the entropy increase is a function of the ratio between the links and the nodes in the network. Therefore, the thermodynamic incentive for a node to join a highly linked network is higher than to join a poorly linked network.

关键词： Information Theory Networks Entropy

Virtual nonenhanced abdominal dual-energy MDCT:Analysis of image characteristics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Radiology 2012年第4期4卷 167-173页

作者： Jacob Sosna Shmuel Mahgerefteh Liran goshen galit kafri galit Aviram Arye Blachar Department of Radiology Hadassah-Hebrew University Medical CenterJerusalem 91120Israel Department of Radiology Beth Israel Deaconess Medical CenterBostonMA 02215United States Philips Healthcare Haifa 31004Israel Department of Radiology Tel Aviv Sourasky Medical CenterSackler School of MedicineTel Aviv UniversityTel Aviv 64239Israel

AIM: To evaluate abdominal and pelvic image characteristics and artifacts on virtual nonenhanced (VNE) images generated from contrast-enhanced dual-energy multidetector computed tomography (MDCT) studies. METHODS: Hadassah-Hebrew University Medical Institutional Review Board approval was obtained; 22 patients underwent clinically-indicated abdominal and pelvic single-source dual-energy MDCT (Philips Healthcare, Cleveland, OH, USA), pre- and post-IV administration of Omnipaque 300 contrast (100 cc). Various solid and vascular structures were evaluated. VNE images were generated from the portal contrast-enhanced phase using probabilistic separation. Contrast-enhanced-, regular nonenhanced (RNE)-, and VNE images were evaluated with a total of 1494 density measurements. The ratio of iodine contrast deletion was calculated. Visualization of calcifications, urinary tract stones, and image artifacts in VNE images were assessed. RESULTS: VNE images were successfully generated in all patients. Significant portal-phase iodine contrast deletion was seen in the kidney (61.7%), adrenal gland (55.3%), iliac artery (55.0%), aorta (51.6%), and spleen (34.5%). Contrast deletion was also significant in the right atrium (RA) (51.5%) and portal vein (39.3%), but insignificant in the iliac vein and inferior vena cava (IVC). Average post contrast-to-VNE HU differences were significant (P ge VNE-to-RNE HU differences were significant in all organs but the prostate and subcutaneous fat: aorta 38.0 (SD 9.3), RA 37.8 (SD 16.1), portal vein 21.8 (SD 12.0), IVC 12.2 (SD 11.6), muscle 3.3 (SD 4.9), liver 5.7 (SD 6.4), spleen 22.3 (SD 9.8), kidney 40.5 (SD 6.8), and adrenal 20.7 (SD 13.5). On VNE images, 196/213 calcifications (92%) and 5/6 renal stones (84%) were visualized. Lytic-like artifacts in the vertebral bodies we

关键词： Abdominal computed tomography Dual-energy computed tomography Pelvic computed tomography Virtual nonenhanced computed tomography