42 research outputs found
Tuning the Level of Concurrency in Software Transactional Memory: An Overview of Recent Analytical, Machine Learning and Mixed Approaches
Synchronization transparency offered by Software Transactional Memory (STM) must not come at the expense of run-time efficiency, thus demanding from the STM-designer the inclusion of mechanisms properly oriented to performance and other quality indexes. Particularly, one core issue to cope with in STM is related to exploiting parallelism while also avoiding thrashing phenomena due to excessive transaction rollbacks, caused by excessively high levels of contention on logical resources, namely concurrently accessed data portions. A means to address run-time efficiency consists in dynamically determining the best-suited level of concurrency (number of threads) to be employed for running the application (or specific application phases) on top of the STM layer. For too low levels of concurrency, parallelism can be hampered. Conversely, over-dimensioning the concurrency level may give rise to the aforementioned thrashing phenomena caused by excessive data contention—an aspect which has reflections also on the side of reduced energy-efficiency. In this chapter we overview a set of recent techniques aimed at building “application-specific” performance models that can be exploited to dynamically tune the level of concurrency to the best-suited value. Although they share some base concepts while modeling the system performance vs the degree of concurrency, these techniques rely on disparate methods, such as machine learning or analytic methods (or combinations of the two), and achieve different tradeoffs in terms of the relation between the precision of the performance model and the latency for model instantiation. Implications of the different tradeoffs in real-life scenarios are also discussed
The PKA-CREB system encoded by the honeybee genome
The cAMP-dependent kinase (PKA) plays a crucial part in long-term memory formation in the honeybee (Apis mellifera). One of the putative substrates of the PKA activity is the cAMP response element binding protein (CREB), a transcription factor in the bZIP protein family. We searched the honeybee genome to characterize genes from the CREB/CREM and the PKA families. We identified two genes that encode regulatory subunits and three genes encode catalytic subunits of PKA. Eight genes code for bZIP proteins, but only one gene was found that encodes a member of the CREB/CREM family. The phylogenetic relationship of these genes was analysed with their Drosophila and human counterparts
The handbook for standardised field and laboratory measurements in terrestrial climate-change experiments and observational studies
Climate change is a worldwide threat to biodiversity and ecosystem structure, functioning, and services. To understand the underlying drivers and mechanisms, and to predict the consequences for nature and people, we urgently need better understanding of the direction and magnitude of climate‐change impacts across the soil–plant–atmosphere continuum. An increasing number of climate‐change studies is creating new opportunities for meaningful and high‐quality generalisations and improved process understanding. However, significant challenges exist related to data availability and/or compatibility across studies, compromising opportunities for data re‐use, synthesis, and upscaling. Many of these challenges relate to a lack of an established “best practice” for measuring key impacts and responses. This restrains our current understanding of complex processes and mechanisms in terrestrial ecosystems related to climate change
Point View in Bird and Flower Painting
在中国传统绘画中,点景是极其重要的一种表达方式。石涛所研究的绘画问题中,情感、理性、力量都是不可缺少的,如何恰当地运用这三者,却有可能导致完全不同的创作结果。而点景正是这三者的集合点,不仅要用心灵去感受自然对象的内在精神,不能因为对象的限制而使感受层次也受到限制,把眼睛之受升华为心理之受。在绘画作品中合理地运用点景能使画家的情感与物象更加融合,画家自身的主观感受在画面上得到充分的体现,以一种小的特殊表现符号流露出画家作品里表达的象征倾向和审美概念,对画面的构图及意境有着画龙点睛的作用。本文以花鸟画点景为研究对象,重点介绍了点景的表现与意义;进一步阐述了点景在传统花鸟画构成中的作用,着重论述其在...The “point view” is extremely important as a means of expression in the traditional Chinese painting. Emotion, rationality and power are essential in the Shi Tao studied painting, and how to properly use them may lead to the creation of a completely different result. For the reason that “point view” is a collection of these three points, shouldn’t we only use the soul to feel the inner spirit of n...学位:文学硕士院系专业:艺术教育学院美术系_美术学学号:1862007115166
Real-time Implementation Of A Fault Location Algorithm For Homogeneous Power Systems
This paper presents the implementation of a distance relay model in a real-time simulation platform. The relay is basically used in this work to locate faults in radial homogeneous (i.e., all sections have the same per unit parameters) transmission and distribution systems. The device can also be used to estimate the fault impedance, assuming it is a constant resistance. The document presents a sensitivity study of the fault location algorithm; that is, the paper analyzes the performance of the algorithm for estimating the fault distance and the fault resistance as a function of several parameters involved in the transient simulation; namely, the time-step size, the fault distance, and resistance values, as well as the system structure and model. Some important issues for real-time implementation are also discussed. © 2014 Brazilian Society for Automatics-SBA.253381388Abourida, S., Dufour, C., Bélanger, J., Lapointe, V., (2003) Real-time, PC-based Simulator of Electric Systems and Drives, , New Orleans: IPSTAlamuti, M.M., Nouri, H., Ciric, R.M., Terzija, V., Intermittent fault location in distribution feeders (2012) IEEE Transactions on Power Delivery, 27 (1), pp. 96-103Apostolopoulos, C.A., Kornes, G.N., Real-time implementation of digital relay models using MATLAB/SIMULINK and RTDS (2010) European Transactions on Electrical Power, 20 (3), pp. 290-305Bouchet, R., Saad, O., Xémard, A., (2007) Module de Protection Générique Sous EMTP-RV, , Hydro-Québec(2006) Relay Software Models for Use with Electromagnetic Transient Analysis Program, , CIGRE Working Group B 5.17, CIGRE Brochure 295http://www.ewh.ieee.org/soc/pes/dsacom/testfeeders/index.html, IEEE Distribution System Analysis Subcommittee, IEEE 34 Node Test Feeder(2005) EMTP Reference Models for Transmission Line Relay Testing, , http://www.pes-psrc.org/Reports/D10_Report_rev0.zip, IEEE Power System Relaying CommitteeIEEE Guide for Determining Fault Location on AC Transmission and Distribution Lines, , IEEE Std C37.114-2004Jiang, Q., Li, X., Wang, B., Wang, H., PMU-based fault location using voltage measurements in large transmission networks (2012) IEEE Transactions on Power Delivery, 27 (3), pp. 1644-1652McLaren, P.G., Kuffel, R., Weirckx, R., Giesbrecht, J., Arendt, L., A real time digital simulator for testing relays (1992) IEEE Transactions on Power Delivery., 7 (1), pp. 207-213Mohan Saha, M., Izykowski, J., Rosolowski, E., (2010) Fault Location on Power Networks, , New York: SpringerMorais De Pereira, C.E., Zanetta Jr., L.C., Fault location in multitapped transmission lines using unsynchronized data and superposition theorem (2011) IEEE Transactions on Power Delivery, 26 (4), pp. 2081-2089Nouri, H., Alamuti, M.M., Comprehensive distribution network fault location using the distributed parameter model (2011) IEEE Transactions on Power Delivery, 26 (4), pp. 2154-2162Ouellette, D.S., Geisbrecht, W.J., Wierckx, R.P., Forsyth, P.A., (2004) Modelling An Impedance Relay Using A Real Time Digital Simulator: 8th IEE International Conference on Developments in Power System ProtectionPereira, C.E.M., Zanetta Jr., L.C., Optimization algorithm for fault location in transmission lines considering current transformers saturation (2005) IEEE Transactions on Power Delivery, 20 (2), pp. 603-608Peterson, J.N., Wall, R.W., Interactive relay controlled power system modeling (1991) IEEE Transactions on Power Delivery, 6 (1), pp. 96-102Wilson, R.E., Nordstrom, J.M., EMTP transient modeling of a distance relay and a comparison with EMTP laboratory testing (1993) IEEE Transactions on Power Delivery, 5 (3), pp. 984-99
Development of a Coronary Heart Disease Risk Prediction Model for Type 1 Diabetes: The Pittsburgh CHD in Type 1 Diabetes Risk Mode
Aim - To create a coronary heart disease (CHD) risk prediction model specific to type 1 diabetes. Methods - Development of the model used data from the Pittsburgh Epidemiology of Diabetes Complications Study (EDC). EDC subjects had type 1 diabetes diagnosed between 1950 and 1980, received their first study exam between 1986 and 1988, and have been followed biennially since. The final cohort for model development consisted of 603 subjects and 46 incident events. Hard CHD was defined as CHD death, fatal/non-fatal MI or Q-waves. Baseline CHD risk factors were tested bivariately and introduced into a Weibull model. The prediction model was externally validated in the EURODIAB Prospective Complications Study. Results - In males, predictors were higher white blood cell count, micro- or macroalbuminuira, lower HDLc and longer diabetes duration. In females, larger waist/hip ratio, higher non-HDLc, higher systolic blood pressure, use of blood pressure medication, and longer diabetes duration were included. Models were robust to internal and external validation procedures. Conclusions - CHD risk prediction models for hard CHD in those with type 1 diabetes should include risk factors not considered by existing models. Using models specifically developed for predicting CHD in type 1 diabetes may allow for more targeted prevention strategie
Comparison of emissions from wood combustion. Part 1: Emission factors and characteristics from different small-scale residential heating appliances considering particulate matter and Polycyclic Aromatic Hydrocarbon (PAH)-related toxicological potential o
An investigation was performed to study the emissions of state of the art Small-scale residential heating appliances. The different combustion systems Were compared at optimal combustion conditions. A comprehensive characterization of released organic species of all combustion systems was performed. An approach Was performed to estimate the toxicity of the emitted particulate matter by the content of polycyclic aromatic hydrocarbons (PAHs). It is based on the proposal of the German Research Foundation (DFG) that the health risk is proportionally summarized by different PAHs with different health risk potentials. This approach allows for a rough but fast comparison of different furnaces by the Calculation of the toxic equivalent (TEQ) value in addition to the emission of particulate matter (pm). Best results Were obtained by combusting wood as pellets in a modern pellet boiler (PM = 11-13 mg MJ(-1) and TEQ = 0:12-0.75 mu g MJ(-1)). On the opposite of the emission scale, the toxic potentials of the typical log wood stave were found to be about 2 orders of higher (pm = 67-119 mg MJ(-1) and TEQ = 14-28 mu g MJ(-1)) compared to the pellet boiler, despite optimized combustion conditions