An integrated approach to cryptographic mitigation of denial-of-service attacks

Gradual authentication is a principle proposed by Meadows as a way to tackle denial-of-service attacks on network protocols by gradually increasing the confidence in clients before the server commits resources. In this paper, we propose an efficient method that allows a defending server to authenticate its clients gradually with the help of some fast-to-verify measures. Our method integrates hash-based client puzzles along with a special class of digital signatures supporting fast verification. Our hash-based client puzzle provides finer granularity of difficulty and is proven secure in the puzzle difficulty model of Chen et al. (2009). We integrate this with the fast-verification digital signature scheme proposed by Bernstein (2000, 2008). These schemes can be up to 20 times faster for client authentication compared to RSA-based schemes. Our experimental results show that, in the Secure Sockets Layer (SSL) protocol, fast verification digital signatures can provide a 7% increase in connections per second compared to RSA signatures, and our integration of client puzzles with client authentication imposes no performance penalty on the server since puzzle verification is a part of signature verification.

(Re)focusing the Lens to Make Diversity and Difference Visible : Teaching for Quality and Equity

Despite the evidence that Australia’s children are learning literacy, there is also significant evidence that the poorest and most disadvantaged children are being left behind. To date our understanding of the place of transitions in this has been limited, although there has been work on the fourth grade slump (Gee, 2000, 2008), the transition from primary years to secondary years (e.g. Bahr & Pendergast, 2007; Pendergast & Bahr, 2005, 2010), and transitions when changing schools (Henderson, 2008). In this chapter, we consider the notion of transitioning, as we unpack issues related to recognising and valuing student diversity and difference. We want to highlight ways of providing high quality and high equity literacy pedagogy and literacy outcomes for middle years students. We will also discuss the importance of recognising that students transit to schools and school learning from other significant contexts, each with their own combinations of literacy practices, rituals and values.

Spatial and temporal analysis of Barmah Forest virus disease in Queensland, Australia

Barmah Forest virus (BFV) disease is one of the most widespread mosquito-borne diseases in Australia. The number of outbreaks and the incidence rate of BFV in Australia have attracted growing concerns about the spatio-temporal complexity and underlying risk factors of BFV disease. A large number of notifications has been recorded continuously in Queensland since 1992. Yet, little is known about the spatial and temporal characteristics of the disease. I aim to use notification data to better understand the effects of climatic, demographic, socio-economic and ecological risk factors on the spatial epidemiology of BFV disease transmission, develop predictive risk models and forecast future disease risks under climate change scenarios. Computerised data files of daily notifications of BFV disease and climatic variables in Queensland during 1992-2008 were obtained from Queensland Health and Australian Bureau of Meteorology, respectively. Projections on climate data for years 2025, 2050 and 2100 were obtained from Council of Scientific Industrial Research Organisation. Data on socio-economic, demographic and ecological factors were also obtained from relevant government departments as follows: 1) socio-economic and demographic data from Australian Bureau of Statistics; 2) wetlands data from Department of Environment and Resource Management and 3) tidal readings from Queensland Department of Transport and Main roads. Disease notifications were geocoded and spatial and temporal patterns of disease were investigated using geostatistics. Visualisation of BFV disease incidence rates through mapping reveals the presence of substantial spatio-temporal variation at statistical local areas (SLA) over time. Results reveal high incidence rates of BFV disease along coastal areas compared to the whole area of Queensland. A Mantel-Haenszel Chi-square analysis for trend reveals a statistically significant relationship between BFV disease incidence rates and age groups (ƒÓ2 = 7587, p<0.01). Semi-variogram analysis and smoothed maps created from interpolation techniques indicate that the pattern of spatial autocorrelation was not homogeneous across the state. A cluster analysis was used to detect the hot spots/clusters of BFV disease at a SLA level. Most likely spatial and space-time clusters are detected at the same locations across coastal Queensland (p<0.05). The study demonstrates heterogeneity of disease risk at a SLA level and reveals the spatial and temporal clustering of BFV disease in Queensland. Discriminant analysis was employed to establish a link between wetland classes, climate zones and BFV disease. This is because the importance of wetlands in the transmission of BFV disease remains unclear. The multivariable discriminant modelling analyses demonstrate that wetland types of saline 1, riverine and saline tidal influence were the most significant risk factors for BFV disease in all climate and buffer zones, while lacustrine, palustrine, estuarine and saline 2 and saline 3 wetlands were less important. The model accuracies were 76%, 98% and 100% for BFV risk in subtropical, tropical and temperate climate zones, respectively. This study demonstrates that BFV disease risk varied with wetland class and climate zone. The study suggests that wetlands may act as potential breeding habitats for BFV vectors. Multivariable spatial regression models were applied to assess the impact of spatial climatic, socio-economic and tidal factors on the BFV disease in Queensland. Spatial regression models were developed to account for spatial effects. Spatial regression models generated superior estimates over a traditional regression model. In the spatial regression models, BFV disease incidence shows an inverse relationship with minimum temperature, low tide and distance to coast, and positive relationship with rainfall in coastal areas whereas in whole Queensland the disease shows an inverse relationship with minimum temperature and high tide and positive relationship with rainfall. This study determines the most significant spatial risk factors for BFV disease across Queensland. Empirical models were developed to forecast the future risk of BFV disease outbreaks in coastal Queensland using existing climatic, socio-economic and tidal conditions under climate change scenarios. Logistic regression models were developed using BFV disease outbreak data for the existing period (2000-2008). The most parsimonious model had high sensitivity, specificity and accuracy and this model was used to estimate and forecast BFV disease outbreaks for years 2025, 2050 and 2100 under climate change scenarios for Australia. Important contributions arising from this research are that: (i) it is innovative to identify high-risk coastal areas by creating buffers based on grid-centroid and the use of fine-grained spatial units, i.e., mesh blocks; (ii) a spatial regression method was used to account for spatial dependence and heterogeneity of data in the study area; (iii) it determined a range of potential spatial risk factors for BFV disease; and (iv) it predicted the future risk of BFV disease outbreaks under climate change scenarios in Queensland, Australia. In conclusion, the thesis demonstrates that the distribution of BFV disease exhibits a distinct spatial and temporal variation. Such variation is influenced by a range of spatial risk factors including climatic, demographic, socio-economic, ecological and tidal variables. The thesis demonstrates that spatial regression method can be applied to better understand the transmission dynamics of BFV disease and its risk factors. The research findings show that disease notification data can be integrated with multi-factorial risk factor data to develop build-up models and forecast future potential disease risks under climate change scenarios. This thesis may have implications in BFV disease control and prevention programs in Queensland.

Using staffing ratios for workforce planning : evidence on nine allied health professions - a narrative review

Background: Modern healthcare managers are faced with pressure to deliver effective, efficient services within the context of fixed budget constraints. This requires decisions regarding the skill mix of the workforce particularly when staffing new services. One measure used to identify numbers and mix of staff in healthcare settings is workforce ratio. The aim of this study was to identify workforce ratios in nine allied health professions and to identify whether these measures are useful for planning allied health workforce requirements. Method: A systematic literature search using relevant MeSH headings of business, medical and allied health databases and relevant grey literature for the period 2000-2008 was undertaken. Results: Twelve articles were identified which described the use of workforce ratios in allied health services. Only one of these was a staffing ratio linked to clinical outcomes. The most comprehensive measures were identified in rehabilitation medicine. Conclusions: The evidence for use of staffing ratios for allied health practitioners is scarce and lags behind the fields of nursing and medicine.

Forecasting the future risk of Barmah Forest Virus disease under climate change scenarios in Queensland, Australia

BACKGROUND Mosquito-borne diseases are climate sensitive and there has been increasing concern over the impact of climate change on future disease risk. This paper projected the potential future risk of Barmah Forest virus (BFV) disease under climate change scenarios in Queensland, Australia. METHODS/PRINCIPAL FINDINGS We obtained data on notified BFV cases, climate (maximum and minimum temperature and rainfall), socio-economic and tidal conditions for current period 2000-2008 for coastal regions in Queensland. Grid-data on future climate projections for 2025, 2050 and 2100 were also obtained. Logistic regression models were built to forecast the otential risk of BFV disease distribution under existing climatic, socio-economic and tidal conditions. The model was applied to estimate the potential geographic distribution of BFV outbreaks under climate change scenarios. The predictive model had good model accuracy, sensitivity and specificity. Maps on potential risk of future BFV disease indicated that disease would vary significantly across coastal regions in Queensland by 2100 due to marked differences in future rainfall and temperature projections. CONCLUSIONS/SIGNIFICANCE We conclude that the results of this study demonstrate that the future risk of BFV disease would vary across coastal regions in Queensland. These results may be helpful for public health decision making towards developing effective risk management strategies for BFV disease control and prevention programs in Queensland.

European Union and the developing nations' external debt : EU-15's debt policy, 1960–2008

This Master's Thesis defines the debt policy of the current European Union Member States towards the developing nations. Since no official policy for debt exists in the EU, it is defined to include debt practices (loans and debt relief in development cooperation) and debt within the EU development policy framework. This study (1) describes how the issue of external debt appears in the development policy framework, (2) compares EU Member States' given loans and debt relief to grants for the developing nations (1960s to the 2000s), and (3) measures the current orientation in ODA of each EU Member State between grant aid and loan aid using the Grant-Loan Index (GLI). Theoretical aspects include reasons for selecting between loans (Bouchet 1987) and grants (Odedokun 2004, O'Brien and Williams 2007), policy context of the EU (Van Reisen 2007) and the meaning of external debt in the set-up between the North and the South. In terms of history, the events and impact of the colonial period (where loans have originated) are overviewed and compared in light of today's policies. Development assistance statistics are derived from the OECD DAC statistics portal and EU development policy framework documents from the EU portal. Methodologically, the structure of this study is from policy analysis (Barrien 1999, Hill 2008, Berndtson 2008), but it has been modified to fit the needs of studying a non-official policy. EU Member States are divided into three groups by Carbone (2007a), the Big-3, Northern and Southern donors, based on common development assistance characteristics. The Grant-Loan Index is used to compare Carbone's model, which measures quality of aid, to the GLI measuring the structure of aid. Results indicate that EU- 15 countries (active in debt practices) differ in terms of timing, stability and equality of debt practices in the long-term (1960s to the 2000s). In terms of current practices, (2000-2008), it is noted that there lies a disparity between the actual practices and the way in which external debt is represented in the development policy framework, although debt practices form a relevant portion of total ODA practices for many EU-15 Member States, the issue itself plays a minor role in development policy documents. Carbone’s group division applies well to the Grant – Loan Index’s results, indicating that countries with similar development policy behaviour have similarities in debt policy behaviour, with one exception: Greece. On the basis of this study, it is concluded that EU development policy framework content in terms of external debt and debt practices are not congruent. The understanding of this disparity between the policy outline and differences in long-term practices is relevant in both, reaching the UN’s Millennium Development Goals, and in the actual process of developing development aid.

Painehaavapotilaille tehtyjen hoitointerventioiden määrä ja tulokset HYKS:n plastiikkakirurgian klinikassa

Keräsimme ICD-10 koodilla L89 HYKS:n plastiikkakirurgian klinikassa hoidetuista 401:stä potilaasta hoitotiedot vuosilta 2000-2008. Plastiikkakirurgiseen leikkaukseen ja hoidon arvioon päätyneiden potilaiden keski-ikä oli 60,3 (18-97v.). Painehaavan riskitekijät selvitettiin. Yksittäisistä riskitekijöistä yleisimpiä olivat paraplegia ( n=77; 17% ) ja diabetes/ASO tauti ( n=53; 12 % ). Yhteensä painehaavaleikkauksia tehtiin 347 , joista revisioleikkauksia 108 ja varsinaisia sulkuleikkauksia oli 239. Keskimäärin potilaat tarvitsivat 1.7 operaatiota. Leikatuista painehaavoista gradus III- haavoja oli 35,1% ; n= 84 ja gradus IV 25,5% ; n= 61, pinta-ala haavoilla oli keskimäärin 30,5 cm2. Istuinkyhmyjen ja sacrumin painehaavat olivat potilasaineistossamme yleisiä (20% ja 27% operoiduista painehaavoista). Gradus III haavoja leikattiin keskimäärin 1,6 kertaa ja gradus IV haavoja keskimäärin 2,0 kertaa. Postoperatiivisia poliklinikkakäyntejä tarvittiin keskimäärin 2,3, gradus III painehaavapotilailla 2,0 ja gradus IV potilailla 2,6 käyntiä. Leikkausmenetelmistä eri kielekerekonstruktiot olivat selkeästi eniten käytetty leikkausmenetelmä painehaavaleikkauksissa: 58 % rekonstruktioleikkauksista suoritettiin käyttäen jonkinlaista iho- lihaskielekettä. (134 sanaa)

Victims of the White War or Rebellions of the Green Revolution? Bolivian Indigenous Women Prisoners' Position in the "War on Drugs" Explored through a Criminological Gaze

Tässä tutkielmassa tarkastellaan Bolivialaisten naisvankien (alkuperäisväestön) ja globaalin huumesodan ("War on Drugs") välistä yhteyttä. Keskustelu sijoitetaan laajemmin kokan viljelyn politiikkaan ja alkuperäisväestön kulttuuriin. Kokaa viljeleviä köyhiä maalaisia, joista huomattava osa on naisia, on vangittu Boliviassa kiihtyvää tahtia viime vuosikymmeninä. Moni naisista on kokan tuotannossa ja kaupassa mukana, sillä se on monesti ainoa keino taloudelliseen selviämiseen. Yleisesti ottaen naisvangit ja naisrikolliset ovat marginaalinen ilmiö. Kansainvälisesti tarkasteltuna naisvankien suhteellinen osuus koko vankilaväestöstä on noin 5,2 % (keskiarvo). Boliviassa osuus on vaihdellut 6,1 %:n ja 17,1 %:n välillä vuosina 2000-2008. Naisvankien määrä yleisesti ottaen on ollut rajussa kasvussa, suurin syy naisten vangitsemiseen on huumausaineisiin liittyvät rikokset. Näyttää myös siltä että vähemmistöt ja etnisen taustan omaavat henkilöt ovat yliedustettuina vankilaväestössä. Bolivia seuraa tätä kansainvälistä trendiä. Tämä tutkielma on rajattu kysymyksiin Bolivian intiaaniperäisten naisten osuudesta maan huumerikollisuudessa, sekä heidän suhteellisen korkeaa vangitsemisastetta selittäviin yhteiskunnallisiin tekijöihin. Kysymykset sukupuolesta, etnisyydestä ja kokan viljelyn politiikasta ovat keskiössä. Yleisiä kriminologisia teorioita peilataan kriittisesti suhteessa aineistoon ja Bolivian kontekstiin. Huumesodan ja Bolivian ankaran huumelainsäädännön seurauksista keskustellaan kriittisesti, sekä pohditaan köyhän alkuperäisväestön massavangitsemisen tarpeellisuutta. Tutkimuskysymykseni ovat: mitkä tekijät selittävät kohtuullisen korkean intiaaniperäisten naisvankien määrän Boliviassa, ja mikä on heidän asemansa globaalissa huumesodassa? Tutkielmassa on analysoitu kvantitatiivista ja kvalitatiivista aineistoa. Päälähteenä on ollut Bolivian tilastokeskuksen tuottamat rikostilastot. Tutkielman tärkeimpänä löydöksenä voidaan pitää havaintoa, että vastoin tiettyjä olettamuksia, intiaaniperäiset naiset ovat hyvinkin aktiivisia perinteisesti miehisiksi käsitetyillä aloilla kuten rikollisuudessa ja politiikassa. Tutkielmassa osoitetaan myös, että pidätysten määrät ovat moninkertaistuneet muutamassa vuosikymmenessä. Koska kokan viljelyssä on kyse pääasiallisesti taloudellisesta toimeentulosta, tämä tutkielma kysyy, onko hengissä pysyminen rikos?

Best Node Selection Through Distributed Fast Variable Power Multiple Access

In many wireless applications, it is highly desirable to have a fast mechanism to resolve or select the packet from the user with the highest priority. Furthermore, individual priorities are often known only locally at the users. In this paper we introduce an extremely fast, local-information-based multiple access algorithm that selects the best node in 1.8 to 2.1 slots,which is much lower than the 2.43 slot average achieved by the best algorithm known to date. The algorithm, which we call Variable Power Multiple Access Selection (VP-MAS), uses the local channel state information from the accessing nodes to the receiver, and maps the priorities into the receive power.It is inherently distributed and scales well with the number of users. We show that mapping onto a discrete set of receive power levels is optimal, and provide a complete characterization for it. The power levels are chosen to exploit packet capture that inherently occurs in a wireless physical layer. The VP-MAS algorithm adjusts the expected number of users that contend in each step and their respective transmission powers, depending on whether previous transmission attempts resulted in capture,idle channel, or collision.

Antenna Selection for Next Generation IEEE 802.16 Mobile Stations

The IEEE 802.16/WiMAX standard has fully embraced multi-antenna technology and can, thus, deliver robust and high transmission rates and higher system capacity. Nevertheless,due to its inherent form-factor constraints and cost concerns, a WiMAX mobile station (MS) should preferably contain fewer radio frequency (RF) chains than antenna elements.This is because RF chains are often substantially more expensive than antenna elements. Thus, antenna selection, wherein a subset of antennas is dynamically selected to connect to the limited RF chains for transceiving, is a highly appealing performance enhancement technique for multi-antenna WiMAX terminals.In this paper, a novel antenna selection protocol tailored for next-generation IEEE 802.16 mobile stations is proposed. As demonstrated by the extensive OPNET simulations, the proposed protocol delivers a significant performance improvement over conventional 802.16 terminals that lack the antenna selection capability. Moreover, the new protocol leverages the existing signaling methods defined in 802.16, thereby incurring a negligible signaling overhead and requiring only diminutive modifications of the standard. To the best of our knowledge, this paper represents the first effort to support antenna selection capability in IEEE 802.16 mobile stations.

Experimental study and simulation principles of an oil-gas multiphase transportation system

Presented is an experimental study on the performance of an oil-gas multiphase transportation system, especially on the multiphase flow patterns, multiphase pumping and multiphase metering of the system. A dynamic simulation analysis is conducted to deduce simulation parameters of the system and similarity criteria under simplified conditions are obtained. The reliability and feasibility of two-phase flow experiment with oil and natural gas simulated by water and air are discussed by using the similarity criteria.

Ensayos de Política Económica, Año VIII, Vol. II, Nº 2, 2014

Contenido: Editorial -- Interaction between a strategic mass media firm and a government / Julián Alberto Batista -- Políticas proteccionistas de la Argentina desde 2003 : del auge a la decadencia económica / Julio J. Nogués -- Lidiando con las estadísticas internacionales en las ciencias sociales / José María Dagnino Pastore ; Luis María Libonatti -- La relación virtuosa de la seguridad y la inversión extranjera directa en Colombia (1994-2013) / Catalina Gómez Toro -- Estimación de la probabilidad de default : un modelo probit para los bancos argentinos / Felipe Klein -- Aproximación a las causas de la desigualdad económica / Maximiliano Mozetic -- Reseñas

集成激光制造系统的开放式控制研究

针对激光制造系统的发展要求,提出了一种开放式集成激光制造系统,该系统将激光器控制模块、测量模块、机器人模块和计算机控制模块等进行集成,采用模块化设计方法,各模块功能独立,实现了主控计算机对各控制模块的协调控制.其中激光器由PROFIBUS-DP现场总线控制,机器人由运动控制器控制.解决了传统激光制造系统结构封闭,专用性强,难于实现柔性化制造的难题.通过实际应用,进一步证明了该系统的开放性和可控性.

BONDING OF ALUMINA AND METAL USING BULK METALLIC GLASS FORMING ALLOY

Metal-alumina joints have found various practical applications in electronic devices and high technology industry. However, making of sound metal ceramic brazed couple is still a challenge in terms of its direct application in the industry. In this work we successfully braze copper with Al2O3 ceramic using Zr52.5Cu17.9Ni14.6Al10Ti5 bulk metallic glass forming alloy as filler alloy. The shear strength of the joints can reach 140 MPa, and the microstructrural analysis confirms a reliable chemical boning of the interface. The results show that the bulk metallic glass forming alloys with high concentration of active elements are prospective for using as filler alloy in metal-ceramic bonding.

EQUIVALENT MODEL OF EXPANSION OF CEMENT MORTAR UNDER SULPHATE EROSION

The expansion property of cement mortar under the attack of sulfate ions is studied by experimental and theoretical methods. First, cement mortars are fabricated with the ratio of water to cement of 0.4, 0.6, and 0.8. Secondly, the expansion of specimen immerged in sulphate solution is measured at different times. Thirdly, a theoretical model of expansion of cement mortar under sulphate erosion is suggested by virtue of represent volume element method. In this model, the damage evolution due to the interaction between delayed ettringite and cement mortar is taken into account. Finally, the numerical calculation is performed. The numerical and experimental results indicate that the model perfectly describes the expansion of the cement mortar.