Counter Part Research Articles

Optical trapping of antihydrogen towards an atomic anti-clock

The Anti-Matter Factory at CERN is gearing up, commissioning of the Extra Low ENergy Antiprotons (ELENA) ring is ongoing and the first anti-protons are foreseen to circulate in the decelerator very soon. The unprecedented flux of low energy antiprotons delivered by ELENA will open a new era for precision tests with antimatter including laser and microwave spectroscopy and tests of its gravitational behaviour. Here we propose a scheme to load the ultra cold anti-hydrogen atoms that will be produced by the GBAR experiment in an optical lattice tuned at the magic wavelength of the 1S-2S transition in order to measure this interval at a level comparable or even better than its matter counter part. This will provide the most sensitive test of CPT symmetry parametrised in the framework of the Standard Model Extension.

Neural spelling correction: translating incorrect sentences to correct sentences for multimedia

The aim of a spelling correction task is to detect spelling errors and automatically correct them. In this paper we aim to perform the Korean spelling correction task from a machine translation perspective, allowing it to overcome the limitations of cost, time and data. Based on a sequence to sequence model, the model aligns its source sentence with an ‘error filled sentence’ and its target sentence aligned to the correct counter part. Thus, ‘translating’ the error sentence to a correct sentence. For this research, we have also proposed three new data generation methods allowing the creation of multiple spelling correction parallel corpora from just a single monolingual corpus. Additionally, we discovered that applying the Copy Mechanism not only resolves the problem of overcorrection but even improves it. For this paper, we evaluated our model upon these aspects: Performance comparisons to other models and evaluation on overcorrection. The results show the proposed model to even out-perform other systems currently in commercial use.

An asymptotically compatible approach for Neumann-type boundary condition on nonlocal problems

In this paper we consider 2D nonlocal diffusion models with a finite nonlocal horizon parameterδcharacterizing the range of nonlocal interactions, and consider the treatment of Neumann-like boundary conditions that have proven challenging for discretizations of nonlocal models. We propose a new generalization of classical local Neumann conditions by converting the local flux to a correction term in the nonlocal model, which provides an estimate for the nonlocal interactions of each point with points outside the domain. While existing 2D nonlocal flux boundary conditions have been shown to exhibit at most first order convergence to the local counter part asδ → 0, the proposed Neumann-type boundary formulation recovers the local case asO(δ2) in theL∞(Ω) norm, which is optimal considering theO(δ2) convergence of the nonlocal equation to its local limit away from the boundary. We analyze the application of this new boundary treatment to the nonlocal diffusion problem, and present conditions under which the solution of the nonlocal boundary value problem converges to the solution of the corresponding local Neumann problem as the horizon is reduced. To demonstrate the applicability of this nonlocal flux boundary condition to more complicated scenarios, we extend the approach to less regular domains, numerically verifying that we preserve second-order convergence for non-convex domains with corners. Based on the new formulation for nonlocal boundary condition, we develop an asymptotically compatible meshfree discretization, obtaining a solution to the nonlocal diffusion equation with mixed boundary conditions that converges withO(δ2) convergence.

The Transmuted Odd Fréchet-G Family of Distributions: Theory and Applications

The last years, the odd Fréchet-G family has been considered with success in various statistical applications. This notoriety can be explained by its simple and flexible exponential-odd structure quite different to the other existing families, with the use of only one additional parameter. In counter part, some of its statistical properties suffer of a lack of adaptivity in the sense that they really depend on the choice of the baseline distribution. Hence, efforts have been made to relax this subjectivity by investigating extensions or generalizations of the odd transformation at the heart of the construction of this family, with the aim to reach new perspectives of applications as well. This study explores another possibility, based on the transformation of the whole cumulative distribution function of this family (while keeping the odd transformation intact), through the use of the quadratic rank transmutation that has proven itself in other contexts. We thus introduce and study a new family of flexible distributions called the transmuted odd Fréchet-G family. We show how the former odd Fréchet-G family is enriched by the proposed transformation through theoretical and practical results. We emphasize the special distribution based on the standard exponential distribution because of its desirable features for the statistical modeling. In particular, different kinds of monotonic and nonmonotonic shapes for the probability density and hazard rate functions are observed. Then, we show how the new family can be used in practice. We discuss in detail the parametric estimation of a special model, along with a simulation study. Practical data sets are handle with quite favorable results for the new modeling strategy.

Empirical Studies of Indigenous and Medicinal Utilization of African Locust Beans (Parkia biglobosa. Jacq Benth) in Zaria Local Government Area of Kaduna State, Nigeria

The study examines the indigenous and medicinal utilization of African locust bean tree Parkia biglobosa) in Zaria Local Government Area of Kaduna State, Nigeria. Twenty (20) questionnaires were randomly administered in each of the six (6) districts to make a total of one hundred and twenty questionnaires (120). Ninety (90) were retrieved. The results show that the species is a multipurpose tree that can be subjected to various indigenous uses such as: root decoction in treatment of coccidiosis in poultry (100%), green pod of the fruit use as a fish poison to catch fish in the rivers (100%), seeds, pods, and fruits use as a drinking ingredients (75%), mature wood of the species are use in light construction of mortars and pestles, different kinds of furniture and utensils (75%) and so on. The result further, revealed that the plant parts (leaves; stem; bark, root, exudates (gum) seed and yellow pulp) is used in treatment and prevention of various diseases such as small pox; pile; malaria; dysentery; diarrhea; leprosy; snake bite; fever; measles, convulsion in infant, liver problem, headache, ear, skin diseases and so on. Demographic characteristic of the respondents was also examined. The percentage of male was (43.34%) while that of their female counter part was (56.66%). Majority (43.33%) of the respondents were between 31 – 40 years’ age bracket and majority (44.44%) are married with majority (37.78%) having 1-5 house hold size. 45.56% of the respondents had secondary education while 2.22% had no formal education and majority (51.11%) are traditional healers. The regression analysis showed significant relationship between age, household size, educational status, occupation and the indigenous and medicinal utilization of African locust bean tree(P<0.05) level of significant. However, it is recommended that sustainability of biological resources should be ensured so that medicinal plants such as Parkia biglobosa do not go into extinction. Also, enforcement of the forestry act with regards to illegal and indiscriminately felling of trees like Parkia biglobosa are highlighted.

On an open problem of S. Fučík

Consider the boundary value problem u′′+u=αu−+p(t), u(0)=0=u(π), α≤0. We show that a necessary and sufficient condition for the problem to be solvable is that ∫0πp(t)sintdt≥0. We thus answer positively a counter part of a long-standing open problem posed by S. Fučík. A more general problem is also considered and the sufficient condition for the existence of solution is obtained.

Some Hard or Soft Coatings to Protect the Pristine Biometallic Substrates under Fretting-Corrosion Solicitations: What Should Be the Best Solution?

Under tribological conditions in aqueous medium, the contact of materials does involve some degradations of materials. Especially friction under small reciprocal displacement, i.e., fretting corrosion, is occurring; this topic has been highlighted since the 80′s regarding hip implants. Hip prosthesis is assembled from three parts: femoral stem, neck and head. Fretting corrosion or friction corrosion between metallic parts first involves some degradation of the oxides layers. This step is governed by mechanics and it is related to some few minutes. Afterwards the corrosion occurrs enhanced by mechanical degradation. As well focused some oxides and some metallic ions are related to biocompatibility issues. Some strategies are available in order to avoid metal against metal friction and/or fretting. Some hard coatings and some smooth coatings were investigated. The first one is diamond-like carbon (DLC), and the second is a polyetheretherketone (PEEK), polymeric one. The investigations were focused on fretting corrosion solicitations of Ti-6Al-4V vs. Ti-6Al-4V + coating. DLC as a coating delays the corrosion degradation. The PEEK coating does not promote any corrosion degradation of the metallic counter part and more generally any wear.

Medicinal Plants Used in the Treatment of Antenatal and Postnatal Disorders in Kaduna Southern Guinea Savanna of Nigeria: Empirical Study of Kachia Local Government Area of Kaduna State, Nigeria

Medicinal plant used in the treatment of ante-natal and post-natal disorders in Kaduna Sothern Guinea Savanna using Kachia Local Government Area of Kaduna State as a case studied was investigated. Twenty-five (25) questionnaires were randomly distributed in each of the four (4) wards to make a total of hundred (100) questionnaires. The data collected was analyzed using frequency distribution table and Chi-square (X2). The result Shows that part of the plant species used in preparation of the herbal used in the treatment of ante natal and post-natal disorders include leaves; roots; bark; fruits; leaves and barks; roots and leaves. A total of fourteen (14) plants species belonging to ten (10) families were documented for antenatal while a total of twelve (12) plants species belonging to ten (10) families were documented for post-natal Majority of the herbs are consumed in fresh forms. Crushing is the major (66.0%) method of preparing the herbal /medicine. Also, drinking method is the major (64.0%) method of administration of the herbs/plants. Based on the result, it was further reveals that anemia (26.0%) had major symptoms associated with ante natal while protracted labour (26.0%) was the major symptoms associated with postnatal. Demographic characteristic of the respondents was also examined. The percentage of male was (15.0%) while that of female counter part was (85.0%). majority (41.0%) of the respondents were between 31-40-years age bracket and 73.0% are married and 58.0% of the respondents had qur’anic education while 12.0% had no formal education and majority (42.0%) of the respondents are traditional practioners. Chi-square(X2) analysis revealed that all the independent variable at (P>0.01) probability level the results gave no significant relationship (P>0.01) with the symptom associated with ante-natal and postnatal and the parts of the plant used. However, it is recommended that modernization of health care in Kaduna Southern Guinea Savanna could benefit from integrating aspect of traditional practice and plant used in to health care modernization programme through active involvement of local people. This would also facilitate the implementation of culturally appropriate health care that respect traditional knowledge and contribute to bio-culturally sustainable development of the area.

Mergers of Banks in Economy – Indian Scenario

Banking area possesses a significant spot in each economy and is one of the quickest developing sectors in India. The challenge is very high and tough from the worldwide player’s i.e. International banks. On the counter part, both public and private banks are also facing strong competition among themselves to reach the targeted audience. But the worrying factor is Non performing assets are also increasing simultaneously with core business. The result is mergers in the banking sector in order to reduce the NPA. The most recent and largest merger in the history of banking industry took place on April 1, 2017 i.e., State bank of India and its associates banks. And, now the govt. of India announces India’s biggest and largest mega banks merger on august 30, 2019, i.e., merging of 10 public sector banks into 4 large banks. These banks are oriental bank of commerce and united bank of India merging with Punjab national bank; Syndicate bank with Canara bank; Andhra bank and corporation bank merging with Union bank of India; and Allahabad bank merging with Indian bank; This merger will bring nearly a half yearly of all outstanding loans in Indian’s banking sector. This big bank merger will be a good move from the central govt. to reach $5 trillion economy in next 5 years. This merger will help to give some boost to the Indian economy, which is suffering with high rate of NPA’S. In this research paper an attempt is made to know the impact of banks performance after merger will really give acceleration to the economic growth rate or not.

Ethnobotanical Survey of Medicinal Utilization and Phytochemical Composition of Baobab Tree (Adansonia digitata L.) in Zaria Local Government Area of Kaduna State, Nigeria

Medicinal utilization and phytochemical composition of Baobab tree (Adansonia digitata L.) in Zaria Local Government Area of Kaduna State was studied. Twenty (20) questionnaires were randomly administered in each of the six (6) districts to make a total of one hundred and twenty questionnaires (120). Ninety (90) were retrieved. The result revealed that the plant parts (leaves; stem; bark and seed) can be used in treatment and prevention of various diseases such as tuberculosis; anemia; malaria; dysentery; diarrhea; joint pains; serves as anti-diabetic; fever; urinary infection e t c. Infusion is the major (43.33%) method of herbal preparation. Parts of the plants species used in preparing the herbs include: the leaves; bark; root; seeds and fruits. Majority of the herbal are consumed in a dried form. Demographic characteristic of the respondents were also examined. The percentage of Male was (43.34%) while that of their female counter part was (56.66%). Majority (43.33%) of the respondents were between 31 – 40 years age bracket and majority (44.44%) are married with majority (37.78%) having 1-5 house hold size. 45.56% of the respondents had secondary education while 2.22% had no formal education and majority (51.11%) are traditional healers. Quantitative phytochemical analysis revealed the presence of tannins; alkaloids flavonoids; terpenoids; saponins and phenolic acid in various concentrations as there were significant differences (p < 0.05) between these phytochemicals and their plants parts. The presence of varied active ingredients in the different parts of these plants explains their diverse use in the treatment of different disease conditions. However, it is recommended that due to the increased interest in baobab products (especially on its medical utilization) and slow growth of the plant research should be directed on how to develop a new cultivar with short maturation period. Also, the local population particularly the youth should be educated and also encouraged to learn more about the tradition medicine knowledge in order to preserve it from being lost with the old genera.

An overview of mechanization in chhana production

Chhana , regarded as the Indian counter part of soft cottage cheese is a heat acid coagulated milk product that serves as the base for a variety of milk products such as rasogolla, sandesh, paneer, cham cham, chhana podo, chhana kheer, kheermohan etc. Process mechanization of chhana and chhana based sweets is of huge scope due to the growing momentum in consumer demand for Traditional Indian milk products. Strengthening the knowledge base available for the technology of production of chhana is required to upgrade the existing systems with process automation and control. The main objective of all new technological interventions and improved mechanization systems for chhana developed so far is on yielding chhana of defined moisture content, soft texture and uniform quality along with reducing the cost and production time. Development of an improved mechanized systems for the rapid and hygienic production of chhana at small scale level is an urgent need of the hour. Mechanizations in various stages of chhana production can be integrated to the continuous system of chhana production. This article highlights the technological interventions and mechanization in the manufacture of chhana. In addition, the effect of coagulants in the manufacture of chhana , nutritive value and textural attributes of chhana are also discussed.

On the Performance of Cell-Free Massive MIMO Relying on Adaptive NOMA/OMA Mode-Switching

The downlink (DL) of a non-orthogonal-multiple-access (NOMA)-based cell-free massive multiple-input multiple-output (MIMO) system is analyzed, where the channel state information (CSI) is estimated using pilots. It is assumed that the users are grouped into multiple clusters. The same pilot sequences are assigned to the users within the same clusters whereas the pilots allocated to all clusters are mutually orthogonal. First, a user's bandwidth efficiency (BE) is derived based on his/her channel statistics under the assumption of employing successive interference cancellation (SIC) at the users' end with no DL training. Next, the classic max-min optimization framework is invoked for maximizing the minimum BE of a user under per-access point (AP) power constraints. The max-min user BE of NOMA-based cell-free massive MIMO is compared to that of its orthogonal multiple-access (OMA) counter part, where all users employ orthogonal pilots. Finally, our numerical results are presented and an operating mode switching scheme is proposed based on the average per-user BE of the system, where the mode set is given by Mode = { OMA, NOMA }. Our numerical results confirm that the switching point between the NOMA and OMA modes depends both on the length of the channel's coherence time and on the total number of users.

Clinicopathological and immunohistochemical study of male breast carcinoma: Experience from a tertiary care teaching hospital of South India

Introduction: Male breast carcinoma (MBC) accounts for 1% of all breast carcinomas. Compare to female counter part, they present with advance stage and high lymph node positivity and carries a poor prognosis. Invasive ductal carcinoma (IDC) no special type was the most common histopathological type. They express high hormonal receptor positivity. Few epidemiological studies of MBC are available in the northern part of India, but studies in the Southern India are spares. Hence, this study was undertaken to document the clinicopathological parameters and IHC profile associated with MBC in this region of India.Materials and Methods: This is a retrospective study for a period of 10 years. Each case was assessed for clinical presentation, laterality, quadrant of the breast involved, fine-needle aspiration cytology diagnosis, mammography, type of surgery, size of tumor, histopathological diagnosis, lymph node status, metastasis, SBR grading, and TNM staging. Immunohistochemical expression of estrogen receptor, progesterone receptor, human epidermal growth factor receptor-2 (Her 2) Neu, and Ki 67 was graded as per the standard protocol.Results: During the study period, 16 MBC were observed, constituting 1.5%. The median age is 59 years; painless lump is the most common presentation. IDC no special type is the most common variant. The left breast was commonly affected (81.25%). None of them had a family history of breast carcinoma; central subareola region is the most common anatomical site involved. 62.5% were in Grade 2 and 28.5% showed ipsilateral axillary lymph node involvement. High hormonal receptor positivity was noted in 100% cases, whereas 12.5% showed Her 2 amplifications.Conclusion: Our study also conclude that the pathology of MBC is as most of the cases are presenting with Stage 2 and less lymph node involvement which may carry a better prognosis; however, more studies on the large sample are required to document the same.

PS I Love You: Privacy Aware Sentiment Classification

At first glance, one might think that people are aware of the availability of comments or posts on social networks. Therefore, one may believe that people do not share sensitive information on public social networks. None theless, people’s posts sometimes reveal susceptible information. These posts include mentions the use of drugs or alcohol, sexual preferences, intimate confessions and even serious medical conditions like cancer or HIV. Such privacy leaks could cost someone to get fired or even worse to be avictim of denial insurance or bad credit evaluations. In this paper, we propose a complete process to performa privacy-preserving sentiment analysis trough Bloom filters. Our approach shows an accuracy difference between 1% and 3% less than their classic sentiment analysis task counter part while guarantying a private aware analysis.

FPGA Realization of Fractional Order Neuron

In this paper fractional Hindmarsh Rose (HR) neuron, which mimics several behaviors of a real biological neuron is implemented on field programmable gate array (FPGA). The results show several differences in the dynamic characteristics of integer and fractional order Hindmarsh Rose neuron models. The integer order model shows only one type of firing characteristics when the parameters of model remains same. The fractional order model depicts several dynamical behaviors even for the same parameters as the order of the fractional operator is varied. The firing frequency increases when the order of the fractional operator decreases. The fractional order is therefore key in determining the firing characteristics of biological neurons. To implement this neuron model first the digital realization of different fractional operator approximations are obtained, then the fractional integrator is used to obtain the low power and low cost hardware realization of fractional HR neuron. The fractional neuron model has been implemented on a low voltage and low power circuit and then compared with its integer counter part. The hardware is used to demonstrate the different dynamical behaviors of fractional HR neuron for different type of approximations obtained for fractional operator in this paper. A coupled network of fractional order HR neurons is also implemented. The results also show that synchronization between neurons increases as long as coupling factor keeps on increasing.

Assessment Of Customer Satisfaction In Banking Services: A Comparison Between State Owned And Private Banks In Axum Town, Ethiopia

Over the past decade, Ethiopia has achieved impressive economic growth averaging close to 11 percent annually. The development of a vibrant and active private banking system that complements existing public sector is important to Ethiopia’s economic progress. Customer satisfaction in the banking industry has become an important factor in determining bank's competitiveness. A systematic continuous measurement of customers’ satisfaction level is necessary. Hence, this study focuses on assessing customer satisfaction in state owned commercial bank (Commercial Bank of Ethiopia) and private commercial banks (Wegagen Bank, Dashen Bank, Anbesa Bank). Extending on the assessment we also conducted a comparative analysis of customer satisfaction among state owned and private banks. In order to acquire sufficient information on both quality and quantity, the researcher employed stratified sampling techniques followed by convenience sampling. Each strata contains representative banks from private and state owned banks. To this end, we collected primary data from 300 respondents. Primary Data is collected using the questionnaire and personal contact approach. The researcher used comparative method of data analysis to interpret the results. The overall comparison among private and state owned banks in Axum town have shown that private bank customers have shown to be more satisfied than their counter part customers. On the other hand, both, private and state owned, banks are too behind in creating a responsive bank to their customers and hence need to work on improving their employees responsiveness towards their customers.

R-Ensembler: A greedy rough set based ensemble attribute selection algorithm with kNN imputation for classification of medical data

Background and ObjectiveRetrieving meaningful information from high dimensional dataset is an important and challenging task. Normally, medical dataset suffers from several issues such as curse of dimensionality problem, uncertainty, presence of missing values, non-relevant and redundant attributes, etc. Any machine learning technique applied on such data (without any preprocessing) by and large takes a considerable amount of computational time and may degrade the performance of the model. MethodsIn this article, R-Ensembler, a parameter free greedy ensemble attribute selection method is proposed adopting the concept of rough set theory by using the attribute-class, attribute-significance and attribute-attribute relevance measures to select a subset of attributes which are most relevant, significant and non-redundant from a pool of different attribute subsets in order to predict the presence or absence of different diseases in medical dataset. The main role of the proposed ensembler is to combine multiple subsets of attributes produced by different rough set filters and to produce an optimal subset of attributes for subsequent classification task. A novel n number of set intersection method is also proposed to reduce the biasness during the time of attribute selection process. Before selecting the minimal attribute set from a given data by the proposed R-Ensembler method, the dataset is preprocessed by the k nearest neighbour (kNN) imputation method for missing value treatment. ResultsExperiments are carried out on seven benchmark medical datasets collected from University of California at Irvine (UCI) repository. The performance of the proposed ensemble method is compared with five state-of-the-art attribute selection algorithms, results of which are measured using three benchmark classifiers viz., Naïve Bayes, decision trees and random forest. Experimental results clearly justify the superiority of the proposed R-Ensembler method over other attribute selection algorithms. Results of paired t-test performed on average accuracies produced by different classifiers simulated on the reduced data sets achieved by the proposed and counter part attribute selection methods confirm the statistical significance of the better reduced attribute subsets achieved by the proposed R-Ensembler method compared to others. ConclusionThe proposed ensemble method turned out to be very effective for selecting high relevant, high significant and less redundant attributes from a pool of different subsets of attributes.

Arc PVD (Cr,Al,Mo)N and (Cr,Al,Cu)N coatings for mobility applications

Efficiency during operation is besides reliability and cost effective production one of the most important demands on machines and components. Especially within the automotive sector, components need to fulfill these requirements. Since the demands for high efficiency and reliability cannot be met solely by typical base materials such as case hardened steels, physical vapor deposition (PVD) coatings for the application on highly loaded components gain increasing importance. A possible approach to reduce friction and wear in tribological systems are triboactive and tribocatalytic coatings which contain triboactive elements such as Mo and Cu which can interact with lubricants and lead to the formation of friction and wear reducing tribochemical reaction layers. Besides coating development, also the design of lubricants is in the focus of research activities to reach friction reductions. Therefore, increasing interest gains towards low viscosity lubricants e.g. for e-mobility applications, since reduced friction would lead to extended range.Within the current work, triboactive (Cr,Al,Mo)N and (Cr,Al,Cu)N, (Cr,Al,Mo,Cu)N coatings were deposited by means of cathodic arc evaporation (Arc PVD) in an industrial scale coating unit. The contents of Mo and Cu were varied. As substrate material the case hardened gear steel AISI 5115 (16MnCr5E) was used. The effects of Mo and Cu on the phase formation were investigated by means of X-ray diffraction (XRD). Analysis of the mechanical properties was conducted by nanoindentation (NI) measurements. Tribological behavior of the coatings was analyzed under continuous sliding conditions in pin on disc (PoD) tribometer under minimum quantity lubrication with lubricant amounts of V = 0.05 ml at a temperature T = 80 °C. As lubricants, a low viscosity lubrication oil and a conventional mineral oil were used. Both lubricants contained sulphur and phosphor (S-P) or sulphur (S) additives. In order to investigate the influence of the counter part material on the tribological behavior, inert Si3N4 balls and 100Cr6 steel balls were used. Initial Hertzian contact pressures were set to pH ≈ 1400 MPa and pH ≈ 1600 MPa, respectively. Wear was analyzed by confocal laserscanning microscopy (CLSM). Tribochemical interactions between the coatings and lubricants were studied by Raman spectroscopy. It was found that tribochemical interactions between Mo of the coatings and S of the lubricants can lead to the in situ formation of MoS2 in tribological contact.

Energy cascades in active-grid-generated turbulent flows

The energy cascade and diverse turbulence properties of active-grid-generated turbulence were studied in a wind tunnel via hot-wire anemometry. To this aim, two active grid protocols were considered. The first protocol is the standard triple-random mode, where the grid motors are driven with random rotation rates and directions, which are changed randomly in time. This protocol has been extensively used due to its capacity to produce higher values of $Re_\lambda$ than its passive counter part, with good statistical homogeneity and isotropy. The second protocol was a static or open grid mode, where all grid blades were completely open, yielding the minimum blockage attainable with our grid. Centreline streamwise profiles were measured for both protocols and several inlet velocities. It was found that the turbulent flow generated with the triple-random protocol evolved in the streamwise direction consistently with an energy dissipation scaling of the form $\varepsilon=C_\varepsilon u^{\prime3}/L$, with $C_\varepsilon$ being a constant, $L$ the longitudinal integral length-scale, and $u^\prime$ the rms of the longitudinal velocity fluctuations. Conversely for the open-static grid, the energy dissipation followed a non-equilibrium turbulence scaling, namely, $C_\varepsilon \sim Re_G/Re_L$, where $Re_G$ is a global Reynolds number based on the inlet conditions of the flow, and $Re_L$ is based on the local properties of the flow downstream the grid. Furthermore, this open-static grid mode scaling exhibits important differences with other grids, as the downstream location of the peak of turbulence intensity is a function of the inlet velocity. It was also found that a rather simple theoretical model can predict the value of $C_\varepsilon$ based on the number density of zero-crossings of the longitudinal velocity fluctuations. This theory is valid for both active grid operating protocols.

Partially ordered data sets and a new efficient method for calculating multivariate conditional value-at-risk

Recent studies in Lee and Prekopa (Oper Res Lett 45:19–24, 2017) and Lee (Oper Res Lett 45:1204–1220, 2017) showed that a union of partially ordered orthants in $$R^n$$ can be decomposed only into the largest and the second largest chains. This allows us to calculate the probability of the union of such events in a recursive manner. If the vertices of such orthants designate p-level efficient points, i.e., the multivariate quantile or the multivariate value-at-risk (MVaR) in $$R^n$$ , then the number of them, say N, is typically very large, which makes it almost impossible to calculate the multivariate conditional value-at-risk (MCVaR) introduced by Prekopa (Ann Oper Res 193(1):49–69, 2012). This is because it takes $$O(2^N)$$ in case of N MVaRs in $$R^n$$ to find the exact value of MCVaR. In this paper, upon the basis of ideas in Lee and Prekopa (Oper Res Lett 45:19–24, 2017) and Lee (Oper Res Lett 45:1204–1220, 2017), together with proper adjustments, we study efficient methods for the calculation of the MCVaR without resorting to an approximation. In fact, the proposed methods not only have polynomial time complexity but also computes the exact value of MCVaR. We also discuss additional benefits MCVaR has to offer over its univariate counter part, the conditional value-at-risk, by providing numerical results. Numerical examples are presented with computing time in both cases of given population and sample data sets.