排序方式: 共有73条查询结果,搜索用时 9 毫秒
1.
A model is presented that yields optimal production rates for a firm producing a contracted order. The model is unique in that it considers the influence of production rate and learning on total program cost. An application to the specific characteristics of two military production programs is presented. As demonstrated by the application, models of this type may be used as decision-making tools when negotiating the cost impact of contract modifications. 相似文献
2.
Soner Coban Omer Gokhan Doluoglu Ibrahim Keles Hakan Demirci Ali Riza Turkoglu Muhammet Guzelsoy 《The aging male》2016,19(2):124-127
Objectives: To investigate the predictive values of free prostate-specific antigen (fPSA), total PSA (tPSA) and age on the prostate volume.Methods: The data of 2148 patients with lower urinary tract symptoms were analyzed retrospectively. The patients who had transrectal ultrasonography guided 10 core biopsies owing to the findings obtained on digital rectal examination and presence of high PSA levels (PSA?=?2.5–10?ng/dl), and proven to have BPH histopathologically were included in the study. Age, tPSA, fPSA and the prostate volumes (PV) of the patients were noted.Results: One thousand patients that fulfilled the inclusion criteria were included in the study. The PV of the patients were significantly correlated with age, tPSA and fPSA (p?0.001 and r?=?0.307, p?0.001 and r?=?0.382, p?0.001 and r?=?0.296, respectively). On linear regression model, fPSA was found as a stronger predictive for PV (AUC?=?0.75, p?0.001) when compared to age (AUC?=?0.64, p?0.001), and tPSA (AUC?=?0.69, p?=?0.013).Conclusions: Although tPSA is an important prognostic factor for predicting PV, the predictive value of fPSA is higher. PV can easily be predicted by using age, and serum tPSA and fPSA levels. 相似文献
3.
In a recent paper, Pinto and Mabert [5] presented a lot-sizing rule and an improvement procedure for the joint lot-sizing problem with zero setup costs. We show that this procedure often yields infeasible schedules. We also present and discuss two interesting properties of the joint lot-sizing problem with zero setup costs. A numerical example to illustrate the second property is provided. 相似文献
4.
Euthanasia and assisted suicide are subject to an ongoing debate and discussed with various aspects. Because physicians are in a profession closely related to euthanasia, their attitudes toward this subject are significant. Thus, research intending to explore their opinions is carried out in many countries. In this study, opinions of the physicians regarding euthanasia's definition, contents, legal aspects, and acceptable conditions for its application are addressed. The questionnaire was given to 949 physicians, more than 1% of the total working in Turkey. Of the physicians who participated in the study, 49.9% agreed with the opinion that euthanasia should be legal in certain circumstances. In addition, 19% had come across a euthanasia request and the majority of physicians (55.9%) believed that euthanasia is applied secretly in the country despite the prohibitory legislation. In conclusion, the authors infer from the study itself and believe that euthanasia should be legal in certain circumstances and that the subject, which is not in the agenda of the Turkish population, should continue to be examined. 相似文献
5.
6.
Murat Iyigun 《Journal of population economics》2005,18(2):301-321
This paper explores the role of geography in early development. It presents a model where the odds of survival are higher
in geographically favorable regions. In such regions, higher life expectancy prompts parents to devote more of their resources
to old-age consumption and enables them to invest relatively more in the quantity and quality of their offspring. Investment
in education, together with population growth, helps geographically-favorable economies to attain high levels of a more educated
population that is necessary for sustained economic growth. The empirical evidence is generally supportive of the view that
geographic attributes influenced regional population levels in Europe and its colonial offshoots around 1500 A.D. and that
they affected population levels and educational attainment in low-income countries of the 1990s.
For useful comments and suggestions I thank the editor, two anonymous referees, Daron Acemoglu, Ann Carlos, Phil Graves, Naci
Mocan, Oded Stark, seminar participants at the University of Colorado at Boulder, the University of Colorado at Denver, and
the 2002 Royal Economic Society Annual Conference. I owe a special debt of gratitude to my advisor Herschel Grossman who passed
away in October 2004 after leaving his mark on many of us in the profession. The standard disclaimer applies.
Responsible editor: Alessandro Cigno. 相似文献
7.
8.
The mixture distribution models are more useful than pure distributions in modeling of heterogeneous data sets. The aim of this paper is to propose mixture of Weibull–Poisson (WP) distributions to model heterogeneous data sets for the first time. So, a powerful alternative mixture distribution is created for modeling of the heterogeneous data sets. In the study, many features of the proposed mixture of WP distributions are examined. Also, the expectation maximization (EM) algorithm is used to determine the maximum-likelihood estimates of the parameters, and the simulation study is conducted for evaluating the performance of the proposed EM scheme. Applications for two real heterogeneous data sets are given to show the flexibility and potentiality of the new mixture distribution. 相似文献
9.
The majoritarian compromise is majoritarian-optimal and subgame-perfect implementable 总被引:2,自引:0,他引:2
It is shown that the Majoritarian Compromise of Sertel (1986) is subgame-perfect implementable on the domain of strict preference profiles, although it fails to be Maskin-monotonic and is hence not implementable in Nash
equilibrium. The Majoritarian Compromise is Pareto-optimal and obeys SNIP (strong no imposition power), i.e. never chooses a strict majority's worst candidate. In fact, it is “majoritarian approving”
i.e. it always picks “what's good for a majority” (alternatives which some majority regards as among the better “effective”
half of the available alternatives). Thus, being Pareto-optimal and majoritarian approving, it is majoritarian-optimal. Finally, the Majoritarian Compromise is measured against various criteria, such as consistency and Condorcet-consistency.
Received: 31 January 1995/Accepted: 22 July 1998 相似文献
10.