Secure elliptic curves in cryptography

Elliptic Curve Cryptography (ECC) is a branch of public-key cryptography based on the arithmetic of elliptic curves. In the short life of ECC, most standards have proposed curves defined over prime finite fields using the short Weierstrass form. However, some researchers have started to propose as a more secure alternative the use of Edwards and Montgomery elliptic curves, which could have an impact in current ECC deployments. This chapter presents the different types of elliptic curves used in Cryptography together with the best-known procedure for generating secure elliptic curves, Brainpool. The contribution is completed with the examination of the latest proposals regarding secure elliptic curves analyzed by the SafeCurves initiative.Acknowledgements: This work has been partly supported by Ministerio de Economía y Competitividad (Spain) under the project TIN2014-55325-C2-1-R (ProCriCiS), and by Comunidad de Madrid (Spain) under the project S2013/ICE-3095-CM (CIBERDINE), cofinanced with the European Union FEDER funds

Replacing Myths With Facts: Sex-Selective Abortion Laws In The United States

Sex selection is the practice of attempting to control the sex of one’s offspring in order to achieve a desired sex. One method of sex selection is sex-selective abortion. Laws banning sex-selective abortion are proliferating in the United States. Eight states have enacted laws prohibiting sexselective abortion. Twenty-one states and the federal government have considered such laws since 2009. Those laws prohibit the performance of an abortion if sought based on the sex of the fetus and provide for both criminal and civil penalties in most cases. A great deal of misinformation exists regarding sex selection in the United States. We have identified six inaccuracies commonly associated with sex-selective abortion and laws prohibiting it. They appear, among other places, in statements made by legislators, testimony submitted to legislatures, and reports issued by legislative committees that have considered or adopted laws banning sexselective abortion. We present each piece of inaccurate information as a “myth.” This Report draws on legal research, empirical analysis of U.S. birth data, field-work, and an extensive review of scholarly publications in social sciences, law and other disciplines to replace these myths with facts. Legislators and proponents of sex-selective abortion bans have consistently referred to the existence of male-biased sex ratios and the practice of sex selection in other parts of the world. Discussions have focused on the problem of “missing women” in China and India in particular. However, China and India are not the only countries with male-biased sex ratios. On the contrary, the two countries with the highest sex ratios at birth are Liechtenstein and Armenia (see discussion of Myth #2 below). Both have higher sex ratios at birth than China and India. Legislators and major news outlets have stated that the United States is one of the few countries that does not prohibit abortion for sex selection purposes. However, the eight states in the United States that currently ban sex-selective abortion are among a small minority of places in the world where it is banned. Only four other countries explicitly prohibit sex-selective abortion: China, Kosovo, Nepal and Vietnam (see discussion of Myth #3 below). Instead, many countries that are concerned about sex selection prohibit the use of technology to sex select prior to implantation of the embryo in the uterus. The main empirical support for the view that Asian Americans are obtaining sex-selective abortions based on son preference in the United States is from a study by economists Douglas Almond and Lena Edlund published in 2008. That study, using United States census data from 2000, found that when foreign-born Chinese, Indians and Koreans have two girls, the sex ratios at the third birth in those families is skewed towards boys. However, in analyzing more recent data from the 2007 to 2011 American Community Survey (ACS), we found that the sex ratios at birth of foreign-born Chinese, Indians and Koreans are not male-biased when all their births are taken into account. In fact, foreign-born Chinese, Indians and Koreans have proportionally more girls than white Americans (see discussion of Myth #5 below). Proponents of sex-selective abortion bans claim they are needed to “prohibit discrimination against the unborn on the basis of sex” and to stop the practice of sex selection among Asian Americans in the United States. As noted, sex-selective abortion is only one among several methods available to select the sex of one’s offspring. None of the laws enacted or proposed in the United States prohibit methods other than abortion, such as sperm sorting or preimplantation genetic diagnosis (see discussion of Myth #1 below). Instead, the laws focus solely on abortion. Moreover, sex-selective abortion bans have not been shown to impact sex ratios in the United States. On the contrary, our study shows that laws in Illinois and Pennsylvania—adopted in 1984 and 1989, respectively—are not associated with changes in sex ratios at birth in those states (see discussion of Myth #4 below). Sex-selective abortion laws are part of the legislative campaign of groups opposed to reproductive rights. The laws are generally proposed by legislators who are anti-abortion. Our analysis found that over 90% of Republican representatives in the six states that enacted bans in the last four years voted for the laws. In contrast, less than 10% of Democrats voted for the bans in four of the six states. In the two states where sex-selective abortion bans achieved meaningful support from Democrats— Oklahoma and South Dakota—laws that restrict access to abortion consistently receive bipartisan support (see discussion of Myth #6 below)

Optimising power transmission options for marine energy converter farms

AbstractThis paper introduces a techno-economic analysis framework to assess different transmission options for marine energy converter (MEC) farms. On the technical front, the feasibility of the transmission options considering supply quality constraints and the optimal sizing of reactive power compensation to allow maximum real power transfer capability in the subsea transmission cable have been considered. The economic viability of different transmission options are measured based on component costs and the costs associated with the transmission losses. A case study has been presented in the paper, which demonstrates the application of this techno-economic analysis framework on a range of MEC farm sizes and distances from the shore. The results characterise the performance of different transmission system options with respect to three key design parameters – distance to shore, array power and transmission voltage – and provide guidance for system design

The just-noticeable difference in speech-to-noise ratio

Just-noticeable differences (JNDs) have been measured for various features of sounds, but despite its importance to communication, there is no benchmark for what is a just-noticeable—and possibly meaningful—difference in speech-to-noise ratio (SNR). SNR plays a crucial role in speech communication for normal-hearing and hearing-impaired listeners. Difficulty hearing speech in background noise—a poor SNR—often leads to dissatisfaction with hearing-assistance devices. While such devices attempt through various strategies to address this problem, it is not currently known how much improvement in SNR is needed to provide a noticeable benefit. To investigate what is a noticeable benefit, we measured the JND in SNR for both normal-hearing and hearing-impaired listeners. Here, we report the SNR JNDs of 69 participants of varying hearing ability, estimated using either an adaptive or fixed-level procedure. The task was to judge which of the two intervals containing a sentence in speech-spectrum noise presented over headphones was clearer. The level of each interval was roved to reduce the influence of absolute level cues. The results of both procedures showed an average SNR JND of 3 dB that was independent of hearing ability. Further experiments using a subset of normal-hearing listeners showed that level roving does elevate threshold. These results suggest that noise reduction schemes may need to achieve a benefit greater than 3 dB to be reliably discriminable

Evaluation of cross-contamination of nylon bags with heavy loaded gasoline fire debris and with automotive paint thinner

Nylon bags are used for packaging fire debris in several countries, particularly in Europe. The possibility of cross-contamination during transport from the fire scene to the laboratory, in normal casework conditions in the UK, was studied for two brands of nylon bags, using simulated heavy loaded fire debris. Three experiments were carried out with each brand, using as sample a piece of cotton fabric soaked with gasoline. One experiment was carried out using automotive paint thinner (oxygenated solvent). Each sample was sealed in a nylon bag and stored in contact with eight empty bags. The empty bags were analysed at regular intervals for a period of time up to eight weeks, using SPME and GC/MS. Cross-contamination was found for components of gasoline (toluene and C2-alkylbenzenes) in the two brands of nylon bags used, after 4 days and 2 weeks. Cross contamination using automotive topcoat thinner was detected after 2 days

Heights of occupied patient beds: a possible risk factor for inpatient falls

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72643/1/j.1365-2702.2007.02086.x.pd

The just meaningful difference in speech-to-noise ratio

The speech-to-noise ratio (SNR) in an environment plays a vital role in speech communication for both normal-hearing (NH) and hearing-impaired (HI) listeners. While hearing-assistance devices attempt to deliver as favorable an SNR as possible, there may be discrepancies between noticeable and meaningful improvements in SNR. Furthermore, it is not clear how much of an SNR improvement is necessary to induce intervention-seeking behavior. Here we report on a series of experiments examining the just-meaningful difference (JMD) in SNR. All experiments used sentences in same-spectrum noise, with two intervals on each trial mimicking examples of pre- and post-benefit situations. Different groups of NH and HI adults were asked (a) to rate how much better or worse the change in SNR was in a number of paired examples, (b) if they would swap the worse for the better SNR (e.g., their current device for another) or (c) if they would be willing to go to the clinic for the given increase in SNR. The mean SNR JMD based on better/worse ratings (one arbitrary unit) was similar to the just-noticeable difference, approximately 3 dB. However, the mean SNR JMD for the more clinically relevant tasks -- willingness (at least 50% of the time) to swap devices or attend the clinic for a change in SNR -- was 6-8 dB regardless of hearing ability. This SNR JMD of the order of 6 dB provides a new benchmark, indicating the SNR improvement necessary to immediately motivate participants to seek intervention

Replacing Myths with Facts: Sex-Selective Abortion Laws in the United States

Several countries in the world have sex ratios at birth that are as high or higher than China and India, including countries with predominantly white populations. Nonetheless, immigrant communities in the United States from China and India are consistently accused of harboring a preference for sons. It is supposedly this preference for sons that leads Asian Americans to abort female fetuses. In response, eight states have enacted bans on sex-selective abortion and 21 states and the United States Congress have considered such bans. Proponents of sex-selective abortion bans claim that the United States is one of the few countries in the world where sex-selective abortion is not prohibited. However, our research reveals that only four countries explicitly prohibit sex-selective abortion and that, instead, many countries that are concerned with sex selection prohibit the practice even before the embryo is implanted in the uterus. Our research also reveals that sex-selective abortion bans are not likely to change sex ratios at birth. In a study we conducted on sex ratios in two states that adopted sex-selective abortion bans over 15 years ago—Illinois and Pennsylvania—we found that the laws were not associated with changes in sex ratios. Laws banning sex-selective abortion purport to combat gender discrimination. However, the text of the laws and the statements made in support of the bans during legislative hearings make it clear that they are intended to place restrictions on abortion services generally. Moreover, the laws purport to solve a problem that may not exist at all in the United States. Rather than changing behavior or addressing a purported problem, sex-selective abortion bans are likely to lead to the denial of health care services to Asian American women. Many of the laws require medical professionals to scrutinize a woman’s reproductive choices. Since it is difficult to determine the true reason a woman has chosen to terminate her pregnancy, medical professionals may err on the side of caution and deny care to women in order to avoid liability under the law, even when a woman is not seeking a sex-selective abortion. Laws banning sex-selective abortion have been enacted on the basis of misinformation and harmful stereotypes about Asian Americans. We do not support the practice of sex selection by any means, but rather than combating discrimination, sex-selective abortion bans perpetuate it