Understanding Algorithm Performance on an Oversubscribed Scheduling Application

The best performing algorithms for a particular oversubscribed scheduling application, Air Force Satellite Control Network (AFSCN) scheduling, appear to have little in common. Yet, through careful experimentation and modeling of performance in real problem instances, we can relate characteristics of the best algorithms to characteristics of the application. In particular, we find that plateaus dominate the search spaces (thus favoring algorithms that make larger changes to solutions) and that some randomization in exploration is critical to good performance (due to the lack of gradient information on the plateaus). Based on our explanations of algorithm performance, we develop a new algorithm that combines characteristics of the best performers; the new algorithms performance is better than the previous best. We show how hypothesis driven experimentation and search modeling can both explain algorithm performance and motivate the design of a new algorithm

Finding ECM-friendly curves through a study of Galois properties

In this paper we prove some divisibility properties of the cardinality of elliptic curves modulo primes. These proofs explain the good behavior of certain parameters when using Montgomery or Edwards curves in the setting of the elliptic curve method (ECM) for integer factorization. The ideas of the proofs help us to find new families of elliptic curves with good division properties which increase the success probability of ECM

New model for inorganic pollutants dissipation on the northern part of the romanian black sea coast

© 2018, Editura Academiei Romane. All rights reserved. Last decades, pollution became one of the significant issues worldwide. Atmospheric pollution has a negative impact on the population health, especially in the urban agglomeration, where the exceedance of the concentration limits of the toxic gases is recorded. Sulphur dioxide is the inorganic pollutants most spread in the atmosphere in industrial areas. One of these areas is situated in Northern part of the Romanian Black Sea Coast. Therefore, we aim at determining a model for SO2 dissipation, based on the data collected at six locations, as a function of the atmospheric variables

Triple valve infective endocarditis - a late diagnosis

Behcet\u27s disease is a systemic vasculitis of unknown aetiology with cardiac involvement as well as damage to other organs. Whether the sterile valvular inflammation which occurs in this autoimmune disease predisposes to bacterial adhesion and infective endocarditis is not yet established. We present the case of a patient with Behcet disease in which transthoracic echocardiography showed mobile masses on the aortic, tricuspid, and mitral valves, leading to multivalvular infective endocarditis diagnosis, possibly in the context of valvular inflammation. The case presented in this article confirms observation of other studies, namely that ultrasonography plays an important role in the diagnosis and evaluation of rheumatic diseases and permits optimal management in daily practice

Cross-Sectional Dating of Novel Haplotypes of HERV-K 113 and HERV-K 115 Indicate These Proviruses Originated in Africa before Homo sapiens

The human genome, human endogenous retroviruses (HERV), of which HERV-K113 and HERV-K115 are the only known full-length proviruses that are insertionally polymorphic. Although a handful of previously published papers have documented their prevalence in the global population; to date, there has been no report on their prevalence in the United States population. Here, we studied the geographic distribution of K113 and K115 among 156 HIV-1+ subjects from the United States, including African Americans, Hispanics, and Caucasians. In the individuals studied, we found higher insertion frequencies of K113 (21%) and K115 (35%) in African Americans compared with Caucasians (K113 9% and K115 6%) within the United States. We also report the presence of three single nucleotide polymorphism sites in the K113 5′ long terminal repeats (LTRs) and four in the K115 5′ LTR that together constituted four haplotypes for K113 and five haplotypes for K115. HERV insertion times can be estimated from the sequence differences between the 5′ and 3′ LTR of each insertion, but this dating method cannot be used with HERV-K115. We developed a method to estimate insertion times by applying coalescent inference to 5′ LTR sequences within our study population and validated this approach using an independent estimate derived from the genetic distance between K113 5′ and 3′ LTR sequences. Using our method, we estimated the insertion dates of K113 and K115 to be a minimum of 800,000 and 1.1 million years ago, respectively. Both these insertion dates predate the emergence of anatomically modern Homo sapiens

Efficient distributed tag-based encryption and its application to group signatures with efficient distributed traceability

In this work, we first formalize the notion of dynamic group signatures with distributed traceability, where the capability to trace signatures is distributed among n managers without requiring any interaction. This ensures that only the participation of all tracing managers permits tracing a signature, which reduces the trust placed in a single tracing manager. The threshold variant follows easily from our definitions and constructions. Our model offers strong security requirements. Our second contribution is a generic construction for the notion which has a concurrent join protocol, meets strong security requirements, and offers efficient traceability, i.e. without requiring tracing managers to produce expensive zero-knowledge proofs for tracing correctness. To dispense with the expensive zero-knowledge proofs required in the tracing, we deploy a distributed tag-based encryption with public verifiability. Finally, we provide some concrete instantiations, which, to the best of our knowledge, are the first efficient provably secure realizations in the standard model simultaneously offering all the aforementioned properties. To realize our constructions efficiently, we construct an efficient distributed (and threshold) tag-based encryption scheme that works in the efficient Type-III asymmetric bilinear groups. Our distributed tag-based encryption scheme yields short ciphertexts (only 1280 bits at 128-bit security), and is secure under an existing variant of the standard decisional linear assumption. Our tag-based encryption scheme is of independent interest and is useful for many applications beyond the scope of this paper. As a special case of our distributed tag-based encryption scheme, we get an efficient tag-based encryption scheme in Type-III asymmetric bilinear groups that is secure in the standard model

A Polynomial-Time Key-Recovery Attack on MQQ Cryptosystems

International audienceWe investigate the security of the family of MQQ public key cryptosystems using multivariate quadratic quasigroups (MQQ). These cryptosystems show especially good performance properties. In particular, the MQQ-SIG signature scheme is the fastest scheme in the ECRYPT benchmarking of cryptographic systems (eBACS). We show that both the signature scheme MQQ-SIG and the encryption scheme MQQ-ENC, although using different types of MQQs, share a common algebraic structure that introduces a weakness in both schemes. We use this weakness to mount a successful polynomial time key-recovery attack. Our key-recovery attack finds an equivalent key using the idea of so-called {\it good keys} that reveals the structure gradually. In the process we need to solve a MinRank problem that, because of the structure, can be solved in polynomial-time assuming some mild algebraic assumptions. We highlight that our theoretical results work in characteristic $2$ which is known to be the most difficult case to address in theory for MinRank attacks. Also, we emphasize that our attack works without any restriction on the number of polynomials removed from the public-key, that is, using the minus modifier. This was not the case for previous MinRank like-attacks against \MQ\ schemes. From a practical point of view, we are able to break an MQQ-SIG instance of $80$ bits security in less than $2$ days, and one of the more conservative MQQ-ENC instances of $128$ bits security in little bit over $9$ days. Altogether, our attack shows that it is very hard to design a secure public key scheme based on an easily invertible MQQ structure

The discovery of endogenous retroviruses

When endogenous retroviruses (ERV) were discovered in the late 1960s, the Mendelian inheritance of retroviral genomes by their hosts was an entirely new concept. Indeed Howard M Temin's DNA provirus hypothesis enunciated in 1964 was not generally accepted, and reverse transcriptase was yet to be discovered. Nonetheless, the evidence that we accrued in the pre-molecular era has stood the test of time, and our hypothesis on ERV, which one reviewer described as 'impossible', proved to be correct. Here I recount some of the key observations in birds and mammals that led to the discovery of ERV, and comment on their evolution, cross-species dispersion, and what remains to be elucidated

A Novel Role for IκBζ in the Regulation of IFNγ Production

IκBζ is a novel member of the IκB family of NFκB regulators, which modulates NFκB activity in the nucleus, rather than controlling its nuclear translocation. IκBζ is specifically induced by IL-1β and several TLR ligands and positively regulates NFκB-mediated transcription of genes such as IL-6 and NGAL as an NFκB binding co-factor. We recently reported that the IL-1 family cytokines, IL-1β and IL-18, strongly synergize with TNFα for IFNγ production in KG-1 cells, whereas the same cytokines alone have minimal effects on IFNγ production. Given the striking similarities between the IL-1R and IL-18R signaling pathways we hypothesized that a common signaling event or gene product downstream of these receptors is responsible for the observed synergy. We investigated IκBζ protein expression in KG-1 cells upon stimulation with IL-1β, IL-18 and TNFα. Our results demonstrated that IL-18, as well as IL-1β, induced moderate IκBζ expression in KG-1 cells. However, TNFα synergized with IL-1β and IL-18, whereas by itself it had a minimal effect on IκBζ expression. NFκB inhibition resulted in decreased IL-1β/IL-18/TNFα-stimulated IFNγ release. Moreover, silencing of IκBζ expression led to a specific decrease in IFNγ production. Overall, our data suggests that IκBζ positively regulates NFκB-mediated IFNγ production in KG-1 cells