Quantum Attack-Resistent Certificateless Multi-Receiver Signcryption Scheme

The existing certificateless signcryption schemes were designed mainly based on the traditional public key cryptography, in which the security relies on the hard problems, such as factor decomposition and discrete logarithm. However, these problems will be easily solved by the quantum computing. So the existing certificateless signcryption schemes are vulnerable to the quantum attack. Multivariate public key cryptography (MPKC), which can resist the quantum attack, is one of the alternative solutions to guarantee the security of communications in the post-quantum age. Motivated by these concerns, we proposed a new construction of the certificateless multi-receiver signcryption scheme (CLMSC) based on MPKC. The new scheme inherits the security of MPKC, which can withstand the quantum attack. Multivariate quadratic polynomial operations, which have lower computation complexity than bilinear pairing operations, are employed in signcrypting a message for a certain number of receivers in our scheme. Security analysis shows that our scheme is a secure MPKC-based scheme. We proved its security under the hardness of the Multivariate Quadratic (MQ) problem and its unforgeability under the Isomorphism of Polynomials (IP) assumption in the random oracle model. The analysis results show that our scheme also has the security properties of non-repudiation, perfect forward secrecy, perfect backward secrecy and public verifiability. Compared with the existing schemes in terms of computation complexity and ciphertext length, our scheme is more efficient, which makes it suitable for terminals with low computation capacity like smart cards.     

The confusion effect from neural networks to reduced predation risk

The confusion effect is often cited as an antipredatory benefitof group living and has been demonstrated by numerous studiesacross a range of taxa. However, there have been relativelyfew studies examining the mechanisms behind the effect and noexperimental test of its supposed theoretical basis (informationdegradation in neural networks) using a natural predator–preypairing. In agreement with other studies, we demonstrate thatattack success of the three-spined stickleback (Gasterosteusaculeatus L.) is reduced by an increase in Daphnia magna groupsize. Neural network models attempt to explain this trend withmultiple prey inducing poor neural mapping of target prey, thusleading to an increase in the spatial error of each attack.We explicitly tested this prediction and demonstrate that thedecrease in attack success by sticklebacks does correspond toan increase in spatial targeting error with larger prey groupsize. Finally, we show that the number of targets, rather thanthe density or area occupied by the group, has the greatesteffect on reducing the rate of attack. These results are discussedin the context of the information processing constraints ofpredators, the ultimate cause of the confusion effect.     

A Novel Approach to Characterize Data Uncertainty in Material Flow Analysis and its Application to Plastics Flows in Austria

Material flow analysis (MFA) is widely used to investigate flows and stocks of resources or pollutants in a defined system. Data availability to quantify material flows on a national or global level is often limited owing to data scarcity or lacking data. MFA input data are therefore considered inherently uncertain. In this work, an approach to characterize the uncertainty of MFA input data is presented and applied to a case study on plastics flows in major Austrian consumption sectors in the year 2010. The developed approach consists of data quality assessment as a basis for estimating the uncertainty of input data. Four different implementations of the approach with respect to the translation of indicator scores to uncertainty ranges (linear‐ vs. exponential‐type functions) and underlying probability distributions (normal vs. log‐normal) are examined. The case study results indicate that the way of deriving uncertainty estimates for material flows has a stronger effect on the uncertainty ranges of the resulting plastics flows than the assumptions about the underlying probability distributions. Because these uncertainty estimates originate from data quality evaluation as well as uncertainty characterization, it is crucial to use a well‐defined approach, building on several steps to ensure the consistent translation of the data quality underlying material flow calculations into their associated uncertainties. Although subjectivity is inherent in uncertainty assessment in MFA, the proposed approach is consistent and provides a comprehensive documentation of the choices underlying the uncertainty analysis, which is essential to interpret the results and use MFA as a decision support tool.     

物质流分析研究述评

物质流分析方法近年来在循环经济和可持续发展研究领域发展迅速。阐述了物质流分析的定义及其与自然生态系统物质流的区别,着重回顾了该研究方法的发展历程,阐明了物质流分析的主要观点、理论基础、研究思路及研究框架,详细阐译和对比分析了物质流分析的六大类指标及分析方法,并在物质流分析框架的基础上,建立循环经济及可持续发展的评价指标体系,并对物质流分析指标体系和方法学的研究意义及其在环境经济学中的地位进行了客观的评价,进而指出了物质流分析方法的不足之处。对物质流分析在不同层次的应用研究也进行了充分的阐述和分析。对物质流分析今后相关领域的进一步研究予以了讨论和展望。     

Modelling the attack success of planktonic predators: patterns and mechanisms of prey size selectivity

A mathematical model of the attack success of planktonic predators(fish larvae and carnivorous copepods) is proposed. Based ona geometric representation of attack events, the model considershow the escape reaction characteristics (speed and direction)of copepod prey affect their probability of being captured.By combining the attack success model with previously publishedhydrodynamic models of predator and prey perception, we examinehow predator foraging behaviour and prey perceptive abilityaffect the size spectra of encountered and captured copepodprey. We examine food size spectra of (i) a rheotactic cruisingpredator, (ii) a suspension-feeding hovering copepod and (iii)a larval fish. For rheotactic predators such as carnivorouscopepods, a central assumption of the model is that attack istriggered by prey escape reaction, which in turn depends onthe deformation rate of the fluid created by the predator. Themodel demonstrates that within a species of copepod prey, theability of larger stages to react at a greater distance fromthe predator results in increased strike distance and, hence,lower capture probability. For hovering copepods, the vorticityfield associated with the feeding current also acts in modifyingthe prey escape direction. The model demonstrates that the reorientationof the prey escape path towards the centre of the feeding current'sflow field results in increased attack success of the predator.Finally, the model examines how variability in the kineticsof approach affects the strike distance of larval fish. In caseswhere observational data are available, model predictions closelyfit observations.     

Metabolic flux analysis in plants: coping with complexity

Theory and experience in metabolic engineering both show that metabolism operates at the network level. In plants, this complexity is compounded by a high degree of compartmentation and the synthesis of a very wide array of secondary metabolic products. A further challenge to understanding and predicting plant metabolic function is posed by our ignorance about the structure of metabolic networks even in well-studied systems. Metabolic flux analysis (MFA) provides tools to measure and model the functioning of metabolism, and is making significant contributions to coping with their complexity.
This review gives an overview of different MFA approaches, the measurements required to implement them and the information they yield. The application of MFA methods to plant systems is then illustrated by several examples from the recent literature. Next, the challenges that plant metabolism poses for MFA are discussed together with ways that these can be addressed. Lastly, new developments in MFA are described that can be expected to improve the range and reliability of plant MFA in the coming years.     

Using Web‐Based Technology to Bring Hands‐On Urban Material Flow Analysis to the Classroom

The main objective of this article is to introduce an open‐source, online software tool called OMAT as a teaching tool for performing economy wide‐material flow analysis (EW‐MFA) at urban or regional level in industrial ecology curricula. To that intent, we present a classroom and project activity that was developed for a masters‐level industrial ecology course offered by the Autonomous University of Barcelona. Insights are provided with regards to the outcome of the classroom exercise as well as lessons learned from both an academic and a software development point of view. The OMAT software provides users with a specialized tool to enter and process MFA data in a simple, intuitive way. The usefulness of OMAT as a teaching tool was tested by engaging students in a classroom activity that entailed using OMAT as a tool to perform an EW‐MFA applied to the Metropolitan Area of Barcelona for the years 2005‐2011. The aim of this exercise was to teach students specific skills required in performing an EW‐MFA, not through theory classes, but hands‐on through a learn‐as‐you‐go approach. The exercise not only equipped the students with knowledge about MFA, but also introduced them to solving problems as a team, meeting project deadlines, and communicating effectively with colleagues from different disciplines and backgrounds. Even though there is room for further improvements, this exercise showed that OMAT provided a useful addition to traditional methods that allowed students to get a more practical and thorough understanding of the MFA methodology.     

A secure smart-work service model based OpenStack for Cloud computing

Cloud computing technology is a general concept and idea such as existing distributed computing, parallel computing, Pervasive computing and Ubiquitous computing. We have been studying OpenStack which was an Open cloud project under the KOREN (Korea Advanced Research Network) environments. In this paper, we propose a secure smart-work service model-based OpenStack. There are mainly two kinds of security breaches that can occur under the proposed environment. Nova is vulnerable to DoS attack in OpenStack. SQL Injection can be attacked in the process during which the user requests authorization, which results in data being saved in Swift. Looking more deeply into these two types of attack, we can divide DoS attack into Jolt2, Tear-drop, and SYN-Flooding attack. We simulated attacks in an experimental environment and summarized the results. With the objective of being able to provide Smart-Work service in the KOREN environment, we proposed solutions to various kinds of attacks against the security system and carried out modeling work with the data from the experiment conducted in the Cloud service environment we examined above.     

Arrhythmogenicity of radiofrequency ablation: Symptomatic non-sustained ventricular tachycardia and frequent premature ventricular ectopics after accessory pathway ablation

Radiofrequency ablation (RFA) has emerged as the preferred treatment modality with high success rate in cases with WPW syndrome. Arrhythmogenic complications are rarely reported after RFA, except for early or late recurrence of accessory pathway (AP) conduction. We present a unique case where the AP was successfully ablated, however, a new monomorphic PVC of similar morphology to the pre-excited beats developed within 30 min of RFA. She required medical management with sotalol to overcome her worsening symptom on follow-up. The ectopics resolved after 4 months.     

Novel Duplicate Address Detection with Hash Function

Duplicate address detection (DAD) is an important component of the address resolution protocol (ARP) and the neighbor discovery protocol (NDP). DAD determines whether an IP address is in conflict with other nodes. In traditional DAD, the target address to be detected is broadcast through the network, which provides convenience for malicious nodes to attack. A malicious node can send a spoofing reply to prevent the address configuration of a normal node, and thus, a denial-of-service attack is launched. This study proposes a hash method to hide the target address in DAD, which prevents an attack node from launching destination attacks. If the address of a normal node is identical to the detection address, then its hash value should be the same as the “Hash_64” field in the neighboring solicitation message. Consequently, DAD can be successfully completed. This process is called DAD-h. Simulation results indicate that address configuration using DAD-h has a considerably higher success rate when under attack compared with traditional DAD. Comparative analysis shows that DAD-h does not require third-party devices and considerable computing resources; it also provides a lightweight security resolution.     

基于自组织特征映射模型(SOFM)网络的中国自然资源生态安全区划

自然资源生态安全是国家安全的重要组成部分,自然资源生态安全区划对保障区域可持续发展提供了重要途径。基于自然资源数据、生态环境数据和相关区划资料,从生态敏感性与生态服务重要性角度构建了自然资源生态安全评价指标体系,进而揭示了中国自然资源生态安全的空间格局;通过建立区划的原则和指标,按照一级区主要反映自然资源空间分布格局,二级区主要揭示自然资源生态安全水平的差异,采用SOFM网络制订了中国自然资源生态安全区划方案。结果显示：(1)中国自然资源生态安全水平整体偏低,以中警与重警状态区域为主,安全和较安全状态的区域仅占24.22%,其中低安全等级区多分布于400mm等降水量线以西的干旱、半干旱区,高安全等级区则集中分布于水热资源与生物资源较为丰富的东南部地区;(2)中国自然资源生态安全区划方案包括8个一级区与27个二级区,总结归纳各大区自然资源的特征和威胁生态安全的问题,并针对二级区自然资源生态安全状况提出了对策建议。研究结果可为分区、分类推进全国自然资源可持续利用和国土空间优化提供理论支持与决策依据。     

Effect of growth rate on mean microfibril angle and cross-sectional shape of tracheids of Norway spruce

The variation of the mean microfibril angle (MFA) and the shape of the cross-section of lumen with the distance from the pith in fast grown Norway spruce were studied by X-ray scattering and optical microscopy. The samples were from stems of a clone of Norway spruce [ Picea abies (L.) Karst.] grown in a fertile site at Nurmijärvi, southern Finland Both the mean MFA and the circularity index of the lumen of the fast-grown trees decreased more gradually as the distance from the pith increased than those in reference trees grown in a medium fertility site. However, in mature wood the mean MFA reached the same level in fast-grown trees as in reference trees (5°–10°) but the cross-sections of the cells remained more circular in fast-grown trees than in reference trees. The dependence of the mean MFA on the distance from the pith was similar for earlywood and latewood, but the values of the mean MFA of latewood were systematically smaller than those of earlywood. Two different X-ray diffraction geometries were compared from the points of view of biology and data analysis.     

Anonymous Three-Party Password-Authenticated Key Exchange Scheme for Telecare Medical Information Systems

Telecare Medical Information Systems (TMIS) provide an effective way to enhance the medical process between doctors, nurses and patients. For enhancing the security and privacy of TMIS, it is important while challenging to enhance the TMIS so that a patient and a doctor can perform mutual authentication and session key establishment using a third-party medical server while the privacy of the patient can be ensured. In this paper, we propose an anonymous three-party password-authenticated key exchange (3PAKE) protocol for TMIS. The protocol is based on the efficient elliptic curve cryptosystem. For security, we apply the pi calculus based formal verification tool ProVerif to show that our 3PAKE protocol for TMIS can provide anonymity for patient and doctor while at the same time achieves mutual authentication and session key security. The proposed scheme is secure and efficient, and can be used in TMIS.     

The role of Arg165 towards base flipping, base stabilization and catalysis in M.HhaI

Arg165 forms part of a previously identified base flipping motif in the bacterial DNA cytosine methyltransferase, M.HhaI. Replacement of Arg165 with Ala has no detectable effect on either DNA or AdoMet affinity, yet causes the base flipping and restacking transitions to be decreased approximately 16 and 190-fold respectively, thus confirming the importance of this motif. However, these kinetic changes cannot account for the mutant's observed 10(5)-fold decreased catalytic rate. The mutant enzyme/cognate DNA cocrystal structure (2.79 A resolution) shows the target cytosine to be positioned approximately 30 degrees into the major groove, which is consistent with a major groove pathway for nucleotide flipping. The pyrimidine-sugar chi angle is rotated to approximately +171 degrees, from a range of -95 degrees to -120 degrees in B DNA, and -77 degrees in the WT M.HhaI complex. Thus, Arg165 is important for maintaining the cytosine positioned for nucleophilic attack by Cys81. The cytosine sugar pucker is in the C2'-endo-C3'-exo (South conformation), in contrast to the previously reported C3'-endo (North conformation) described for the original 2.70 A resolution cocrystal structure of the WT M.HhaI/DNA complex. We determined a high resolution structure of the WT M.HhaI/DNA complex (1.96 A) to better determine the sugar pucker. This new structure is similar to the original, lower resolution WT M.HhaI complex, but shows that the sugar pucker is O4'-endo (East conformation), intermediate between the South and North conformers. In summary, Arg165 plays significant roles in base flipping, cytosine positioning, and catalysis. Furthermore, the previously proposed M.HhaI-mediated changes in sugar pucker may not be an important contributor to the base flipping mechanism. These results provide insights into the base flipping and catalytic mechanisms for bacterial and eukaryotic DNA methyltransferases.     

A Data Characterization Framework for Material Flow Analysis

The validity of material flow analyses (MFAs) depends on the available information base, that is, the quality and quantity of available data. MFA data are cross‐disciplinary, can have varying formats and qualities, and originate from heterogeneous sources, such as official statistics, scientific models, or expert estimations. Statistical methods for data evaluation are most often inadequate, because MFA data are typically isolated values rather than extensive data sets. In consideration of the properties of MFA data, a data characterization framework for MFA is presented. It consists of an MFA data terminology, a data characterization matrix, and a procedure for database analysis. The framework facilitates systematic data characterization by cell‐level tagging of data with data attributes. Data attributes represent data characteristics and metainformation regarding statistical properties, meaning, origination, and application of the data. The data characterization framework is illustrated in a case study of a national phosphorus budget. This work furthers understanding of the information basis of material flow systems, promotes the transparent documentation and precise communication of MFA input data, and can be the foundation for better data interpretation and comprehensive data quality evaluation.     

Dynamic changes in prey choice by stickleback during simultaneous encounter with large prey

When a three-spined stickleback Gasterosteus aculeatus encountered prey simultaneously the probability of hanging and the median pursuit time were greater than when prey were encountered sequentially. During simultaneous prey encounter fish did not choose to attack the more profitable prey but instead the nearer prey was handled first except when the difference between the two prey sizes was large. No difference was found in the level of total energetic intake by the fish regardless of prey size pairing. Fish that handled and ate the first prey of a pair in <5 s attacked the second prey with a high probability of success, demonstrating an opportunistic feeding strategy. Importantly however, the fish did not choose to maximize long term energy intake rate by eating both prey, but rather short-term considerations over the course of feeding took precedence. With an empty stomach, the probability of a fish eating ( P _eat) the first prey handled was high regardless of prey size. As stomach fullness increased, the P _eat the first prey handled decreased if it was the larger prey. Hence, the fish were unselective when the stomach was empty but thereafter there was a shift in preference towards the smaller prey. The decision of which prey to attack and eat appeared to be based on short-term energy considerations and the level of stomach fullness. This study demonstrates that feeding on a short-term scale is a crucial factor to take account of when analysing fish feeding during simultaneous prey encounter.     

Adaptive Sex‐Specific Cognitive Bias in Predation Behaviours of Japanese Pygmy Squid

Errors in decision‐making in animals can be partially explained by adaptive evolution, and error management theory explains that cognitive biases result from the asymmetric costs of false‐positive and false‐negative errors. Error rates that result from the cognitive bias may differ between sexes. In addition, females are expected to have higher feeding rates than males because of the high energy requirements of gamete production. Thus, females may suffer relatively larger costs from false‐negative errors (i.e. non‐feeding) than males, and female decisions would be biased to reduce these costs if the costs of false‐positive errors are not as high. Females would consequently overestimate their capacity in relation to the probability of predation success. We tested this hypothesis using the Japanese pygmy squid Idiosepius paradoxus. Our results show that size differences between the squid and prey shrimp affected predatory attacks, and that predatory attacks succeeded more often when the predator was relatively larger than the prey. Nevertheless, compared to male predatory attacks, female squid frequently attacked even if their size was relatively small compared to the prey, suggesting that the females overestimated their probability of success. However, if the females failed in the first attack, they subsequently adjusted their attack threshold: squid did not attack again if the prey size was relatively larger. These results suggest a sex‐specific cognitive bias, that is females skewed judgment in decision‐making for the first predation attack, but they also show that squid can modify their threshold to determine whether they should attack in subsequent encounters.     

从系统到景观:区域物质流分析的景观取向

物质流过程是考察系统属性的重要维度。区域物质流分析在研究框架、指标体系、数据集成、管理应用等方面的发展困境,都不同程度地反映了"黑箱假设"以及"系统隐喻"等产业生态学理论的应用局限性。基于整合复杂性科学、广义进化论的生态学组织层次理论,对区域物质流分析开展理论探讨,指出应在原有的"系统"思维之外引入"景观"概念,以拓展区域物质流分析的空间与认知维度。基于"从系统到景观"的理念,将景观生态学原理引入区域物质流分析,建构区域物质流分析的景观取向,并从空间结构与认知图式两个方面对这一取向的核心涵义做以解读。结合区域物质流分析的最新研究案例,从多尺度MFA的综合研究框架、物质流动过程的时空集成研究、物质流动过程的空间行为管理等几个方面,对区域物质流分析的景观取向做了进一步探讨。