Using system simulation to search for the optimal multi-ordering policy for perishable goods

[EN] This paper explores the possibility that perishable goods can be ordered several times in a single period after considering the cost of Marginal contribution, Marginal loss, Shortage, and Purchasing under stochastic demand. In order to determine the optimal ordering quantity to improve the traditional newsvendor and maximize the total expected profits, and then sensitivity analysis is taken to realize the influence of the parameters on total expected profits and decision variables respectively. In addition, this paper designed a multi-order computerized system with Monte Carlo method to solve the optimal solution under stochastic demand. Based on numerical examples, this paper verified the feasibility and efficiency of the proposed model. Finally, several specific conclusions are drawn for practical applications and future studies.Huang, Y.; Chang, X.; Ding, Y. (2019). Using system simulation to search for the optimal multi-ordering policy for perishable goods. International Journal of Production Management and Engineering. 7(1):49-62. https://doi.org/10.4995/ijpme.2019.10745SWORD496271Azoury, K.S., Miller, B.L. (1984). A comparison of the optimal ordering levels of bayesian and non-bayesian inventory models, Management Science, 30(8), 993-1003. https://doi.org/10.1287/mnsc.30.8.993Alfares, H.K., Elmorra, H.H. (2005). The distribution-free newsboy problem: extensions to the shortage penalty case, International Journal of Production Economics, 93-94(8), 465-477. https://doi.org/10.1016/j.ijpe.2004.06.043Chung, C.S., Flynn, J. (2001). A newsboy problem with reactive production, Computers & Operations Research, 28(8), 751-765. https://doi.org/10.1016/S0305-0548(00)00006-XChun, Y.H. (2003). Optimal pricing and ordering policies for perishable commodities, European Journal of Operational Research, 144(1), 68-82. https://doi.org/10.1016/S0377-2217(01)00351-4Chen, L.H., Chen, Y.C. (2009). A newsboy problem with a simple reservation arrangement. Computers & Industrial Engineering, 56(1), 157-160. https://doi.org/10.1016/j.cie.2008.04.010Dian, J.R. (1990). A high-low search algorithm for a newsboy problem with delayed information feedback. Operations Research, 38(5), 838-846. https://doi.org/10.1287/opre.38.5.838Dye, C.Y., Ouyang, L.Y. (2005). An EOQ model for perishable items under stock-dependent selling rate and time-dependent partial backlogging. European Journal of Operational Research, 163(3), 776-783. https://doi.org/10.1016/j.ejor.2003.09.027Fujiwara, O., Soewandi, H., Sedarage, D. (1997). An optimal ordering and issuing policy for a two-stage inventory system for perishable products. European Journal of Operational Research, 99(2), 412-424. https://doi.org/10.1016/S0377-2217(95)00365-7Gallego, G., Moon, I. (1993). The distribution free newsboy problem: review and extensions. Journal of the Operational Research Society, 44(8), 825-834. https://doi.org/10.1057/jors.1993.141Khouja, M. (1999). The single-period (news-vendor) problem: literature review and suggestions for future research. Omega, 27(5), 537-553. https://doi.org/10.1016/S0305-0483(99)00017-1Khouja, M.J. (2000). Optimal ordering, discounting, and pricing in the single-period problem. International Journal of Production Economics, 65(2), 201-216. https://doi.org/10.1016/S0925-5273(99)00027-4Lau, H., Lau, H. (1998). Decision models for single-period products with two ordering opportunities. International Journal of Production Economics, 55(1), 57-70. https://doi.org/10.1016/S0925-5273(98)00040-1Padmanabhan, G., Vrat, P. (1995). EOQ models for perishable items under stock dependent selling rate. European Journal of Operational Research, 86(2), 281-292. https://doi.org/10.1016/0377-2217(94)00103-JPando, V., Luis, A.S.J., Juan, G.L., Sicilia, J. (2013). A newsboy problem with an emergency order under a general backorder rate function. Omega, 41(6), 1020-1028. https://doi.org/10.1016/j.omega.2013.01.003Zheng, M., Wu, K., Shu, Y. (2016). Newsvendor problems with demand forecast updating and supply constraints. Computers & Operations Research, 67, 193-206. https://doi.org/10.1016/j.cor.2015.10.00

A negative mass theorem for surfaces of positive genus

We define the "sum of squares of the wavelengths" of a Riemannian surface (M,g) to be the regularized trace of the inverse of the Laplacian. We normalize by scaling and adding a constant, to obtain a "mass", which is scale invariant and vanishes at the round sphere. This is an anlaog for closed surfaces of the ADM mass from general relativity. We show that if M has positive genus then on each conformal class, the mass attains a negative minimum. For the minimizing metric, there is a sharp logarithmic Hardy-Littlewood-Sobolev inequality and a Moser-Trudinger-Onofri type inequality.Comment: 8 page

Search for Higgs bosons decaying to tautau pairs in ppbar collisions at sqrt(s) = 1.96 TeV

We present a search for the production of neutral Higgs bosons decaying into tautau pairs in ppbar collisions at a center-of-mass energy of 1.96 TeV. The data, corresponding to an integrated luminosity of 5.4 fb-1, were collected by the D0 experiment at the Fermilab Tevatron Collider. We set upper limits at the 95% C.L. on the product of production cross section and branching ratio for a scalar resonance decaying into tautau pairs, and we then interpret these limits as limits on the production of Higgs bosons in the minimal supersymmetric standard model (MSSM) and as constraints in the MSSM parameter space.Comment: 7 pages, 5 figures, submitted to PL

Measurement of the photon+b+b-jet production differential cross section in ppˉp\bar{p} collisions at \sqrt{s}=1.96~\TeV

We present measurements of the differential cross section dsigma/dpT_gamma for the inclusive production of a photon in association with a b-quark jet for photons with rapidities |y_gamma|< 1.0 and 30<pT_gamma <300 GeV, as well as for photons with 1.5<|y_gamma|< 2.5 and 30< pT_gamma <200 GeV, where pT_gamma is the photon transverse momentum. The b-quark jets are required to have pT>15 GeV and rapidity |y_jet| < 1.5. The results are based on data corresponding to an integrated luminosity of 8.7 fb^-1, recorded with the D0 detector at the Fermilab Tevatron $p\bar{p}$ Collider at sqrt(s)=1.96 TeV. The measured cross sections are compared with next-to-leading order perturbative QCD calculations using different sets of parton distribution functions as well as to predictions based on the kT-factorization QCD approach, and those from the Sherpa and Pythia Monte Carlo event generators.Comment: 10 pages, 9 figures, submitted to Phys. Lett.

Limits on anomalous trilinear gauge boson couplings from WW, WZ and Wgamma production in pp-bar collisions at sqrt{s}=1.96 TeV

We present final searches of the anomalous gammaWW and ZWW trilinear gauge boson couplings from WW and WZ production using lepton plus dijet final states and a combination with results from Wgamma, WW, and WZ production with leptonic final states. The analyzed data correspond to up to 8.6/fb of integrated luminosity collected by the D0 detector in pp-bar collisions at sqrt{s}=1.96 TeV. We set the most stringent limits at a hadron collider to date assuming two different relations between the anomalous coupling parameters Delta\kappa_\gamma, lambda, and Delta g_1^Z for a cutoff energy scale Lambda=2 TeV. The combined 68% C.L. limits are -0.057<Delta\kappa_\gamma<0.154, -0.015<lambda<0.028, and -0.008<Delta g_1^Z<0.054 for the LEP parameterization, and -0.007<Delta\kappa<0.081 and -0.017<lambda<0.028 for the equal couplings parameterization. We also present the most stringent limits of the W boson magnetic dipole and electric quadrupole moments.Comment: 10 pages, 5 figures, submitted to PL

Measurements of inclusive W+jets production rates as a function of jet transverse momentum in ppbar collisions at sqrt{s}=1.96 TeV

This Letter describes measurements of inclusive W (--> e nu) + n jet cross sections (n = 1-4), presented as total inclusive cross sections and differentially in the nth jet transverse momentum. The measurements are made using data corresponding to an integrated luminosity of 4.2 fb-1 collected by the D0 detector at the Fermilab Tevatron Collider, and achieve considerably smaller uncertainties on W +jets production cross sections than previous measurements. The measurements are compared to next-to-leading order perturbative QCD (pQCD) calculations in the n =1-3 jet multiplicity bins and to leading order pQCD calculations in the 4-jet bin. The measurements are generally in agreement with pQCD predictions, although certain regions of phase space are identified where the calculations could be improved

Search for pair production of the scalar top quark in muon+tau final states

We present a search for the pair production of scalar top quarks ($\tilde{t}_{1}$), the lightest supersymmetric partners of the top quarks, in $p\bar{p}$ collisions at a center-of-mass energy of 1.96 TeV, using data corresponding to an integrated luminosity of {7.3 $fb^{-1}$} collected with the \dzero experiment at the Fermilab Tevatron Collider. Each scalar top quark is assumed to decay into a $b$ quark, a charged lepton, and a scalar neutrino ($\tilde{\nu}$). We investigate final states arising from $\tilde{t}_{1} \bar{\tilde{t}_{1}} \rightarrow b\bar{b}\mu\tau \tilde{\nu} \tilde{\nu}$ and $\tilde{t}_{1} \bar{\tilde{t}_{1}} \rightarrow b\bar{b}\tau\tau \tilde{\nu} \tilde{\nu}$. With no significant excess of events observed above the background expected from the standard model, we set exclusion limits on this production process in the ($m_{\tilde{t}_{1}}$,$m_{\tilde{\nu}}$) plane.Comment: Submitted to Phys. Lett.

Search for Higgs bosons of the minimal supersymmetric standard model in p-pbar collisions at sqrt(s)=1.96 TeV

We report results from searches for neutral Higgs bosons produced in p-pbar collisions recorded by the Dzero experiment at the Fermilab Tevatron Collider. We study the production of inclusive neutral Higgs boson in the tautau final state and in association with a b quark in the btautau and bbb final states. These results are combined to improve the sensitivity to the production of neutral Higgs bosons in the context of the minimal supersymmetric standard model (MSSM). The data are found to be consistent with expectation from background processes. Upper limits on MSSM Higgs boson production are set for Higgs boson masses ranging from 90 to 300 GeV. We exclude tanBeta>20-30 for Higgs boson masses below 180 GeV. These are the most stringent constraints on MSSM Higgs boson production in p-pbar collisions.Comment: Submitted to Phys. Lett.

Genome-Wide Association Study for Incident Myocardial Infarction and Coronary Heart Disease in Prospective Cohort Studies: The CHARGE Consortium

Background Data are limited on genome-wide association studies (GWAS) for incident coronary heart disease (CHD). Moreover, it is not known whether genetic variants identified to date also associate with risk of CHD in a prospective setting. Methods We performed a two-stageGWAS analysis of incident myocardial infarction (MI) and CHD in a total of 64,297 individuals (including 3898MI cases, 5465 CHD cases). SNPs that passed an arbitrary threshold of 5×10-6 in Stage I were taken to Stage II for further discovery. Furthermore, in an analysis of prognosis, we studied whether known SNPs from former GWAS were associated with totalmortality in individuals who experienced MI during follow-up. Results In Stage I 15 loci passed the threshold of 5×10-6; 8 loci for MI and 8 loci for CHD, for which one locus overlapped and none were reported in previous GWAS meta-analyses. We took 60 SNPs representing these 15 loci to Stage II of discovery. Four SNPs near QKI showed nominally significant association with MI (p-value<8.8×10-3) and three exceeded the genome-wide significance threshold when Stage I and Stage II results were combined (top SNP rs6941513: p = 6.2×10-9). Despite excellent power, the 9p21 locus SNP (rs1333049) was only modestly associated with MI (HR = 1.09, p-value = 0.02) and marginally with CHD (HR = 1.06, p-value = 0.08). Among an inception cohort of those who experienced MI during follow-up, the risk allele of rs1333049 was associated with a decreased risk of subsequent mortality (HR = 0.90, p-value = 3.2×10-3). Conclusions QKI represents a novel locus that may serve as a predictor of incident CHD in prospective studies. The association of the 9p21 locus both with increased risk of first myocardial infarction and longer survival after MI highlights the importance of study design in investigating genetic determinants of complex disorders

Measurement of the forward-backward asymmetry in Λ0b and Λ¯0b baryon production in pp¯ collisions at s√=1.96 TeV

We measure the forward-backward asymmetry in the production of Λ0b and Λ¯0b baryons as a function of rapidity in pp¯ collisions at s√=1.96  TeV using 10.4  fb−1 of data collected with the D0 detector at the Fermilab Tevatron collider. The asymmetry is determined by the preference of Λ0b or Λ¯0b particles to be produced in the direction of the beam protons or antiprotons, respectively. The measured asymmetry integrated over rapidity y in the range 0.1<|y|<2.0 is A=0.04±0.07(stat)±0.02(syst)