Performance Of Estimation Methods Research Articles

Confirming the Actual Energy Efficiency for Commissioned Buildings

The article provides an overview of the legislative and regulatory base used in the modern system of technical regulations in the Russian Federation in terms of improving the energy efficiency of buildings. The author shows the necessity for the experimental research to find the basis for standard regulations to implement the legislative requirements for actual confirming the building energy efficiency in practice. The results obtained provide a verification method for energy performance estimation based on calculation of the energy performance certificate with the help of factual values of the heat and power indicators.

Substation Lightning Performance Estimation Due to Strikes Into Connected Overhead Lines

The generalization of the probabilistic lightning limiting parameter (LLP) method for high-voltage substation lightning performance estimation due to the discharges into connected overhead lines (OHLs) is described. The method improvement is made only for the case of lightning strokes to the shield wire of OHL, causing back-flashover in front of the substation. The improved LLP method is illustrated at the insulation coordination study of the 400-kV line with long connecting cable with direct entry into the gas-insulated substation of the hydroelectric plant. The number of surge arrester sets and sensitivity analyses of the number of connected step-up transformers influence to the mean time between failures of the 400-kV transformer and equipment insulation are investigated.

Bayesian framework for bilateral teleoperation systems over unreliable network

SUMMARYIn this paper, we present a novel stochastic framework for network-based bilateral teleoperation systems. A Bayesian approach, which provides robust tracking performance in real-world applications, is proposed to estimate and predict the stochastic variables and compensate for the unreliable network conditions. Combining with a practical approach in transport and application layers of the Internet, this paper demonstrates a high performance and efficient prediction and estimation method for bilateral teleoperation system. Experimental results show that the proposed Bayesian approach estimates and predicts true position and force data over unreliable network conditions, and therefore, improves the performance of overall teleoperation systems.

Fatigue performance of deepwater SCR under short-term VIV considering various S-N curves

In this study, a method for fatigue performance estimation of deepwater steel catenary riser (SCR) under short-term vortex-induced vibration was investigated for selected S-N curves. General tendency between S-N curve capacity and fatigue performance was analysed. SCRs are generally used to transport produced oil and gas or to export separated oil and gas, and are exposed to various environmental loads in terms of current, wave, wind and others. Current is closely related with VIV and it affects fatigue life of riser structures significantly. In this regards, the process of appropriate S-N curve selection was performed in the initial design stage based on the scale of fabrication-related initial imperfections such as welding, hot spot, crack, stress concentration factor, and others. To draw the general tendency, the effects of stress concentration factor (SCF), S-N curve type, current profile, and three different sizes of SCRs were considered, and the relationship between S-N curve capacity and short-term VIV fatigue performance of SCR was derived. In case of S-N curve selection, DNV (2012) guideline was adopted and four different current profiles of the Gulf of Mexico (normal condition and Hurricane condition) and Brazil (Amazon basin and Campos basin) were considered. The obtained results will be useful to select the S-N curve for deepwater SCRs and also to understand the relationship between S-N curve capacity and short-term VIV fatigue performance of deepwater SCRs.

Profiling and annotation combined method for multimedia application specific MPSoC performance estimation

Accurate and fast performance estimation is necessary to drive design space exploration and thus support important design decisions. Current techniques are either time consuming or not accurate enough. In this paper, we solve these problems by presenting a hybrid method for multimedia multiprocessor system-on-chip (MPSoC) performance estimation. A general coverage analysis tool GNU gcov is employed to profile the execution statistics during the native simulation. To tackle the complexity and keep the analysis and simulation manageable, the orthogonalization of communication and computation parts is adopted. The estimation result of the computation part is annotated to a transaction accurate model for further analysis, by which a gradual refinement of MPSoC performance estimation is supported. The implementation and its experimental results prove the feasibility and efficiency of the proposed method.

Aero Gas Turbine Flight Performance Estimation Using Engine Gas Path Measurements

Mature gas turbine performance simulation technology has been developed in the past decades and, therefore, gas turbine performance at different ambient and operating conditions can be well predicted if good thermodynamic performance software and necessary engine performance information are available. However, the performance of gas turbine engines of the same fleet may be slightly different from engine to engine due to manufacturing and assembly tolerance and may change over time due to engine degradation. Therefore, it is necessary to monitor and track important performance parameters of gas turbine engines, particularly those that cannot be directly measured, to ensure safe operation of the engines. For that reason, a novel gas turbine performance estimation method using engine gas path measurements has been developed to predict and track engine performance parameters at different ambient, flight, degraded, and part-load operating conditions. The method is based on the influence coefficient matrix of thermodynamic performance parameters of gas turbine engines and the Newton–Raphson mathematical algorithm. Contrary to the conventional gas turbine off-design performance predictions where component characteristic maps are essential, it has the advantage that no component characteristic maps are required for the predictions and, therefore, it is relatively simple thermodynamically, fast in calculation, and desirable in engineering applications. It is able to make important invisible performance parameters visible to gas turbine users, which is a useful complement to current engine condition monitoring techniques. The developed method was applied to the performance prediction of a model gas turbine engine similar to EJ200 low-bypass turbofan engine running at different altitudes, Mach numbers, and part load, with and without degradation, by using simulated gas path measurements to test the effectiveness of the method. The results show that the method is able to predict the engine performance with good accuracy without the consideration of measurement noise and with slightly lower accuracy when measurement noise is included. It takes about 30 s for a typical prediction point, which is suitable for offline performance tracking and condition monitoring. Theoretically, the method can be applied to the performance estimation of any types of gas turbine engines.

Global Performance Estimation Based on Gaussian Mixture Model for Wind Turbines

In order to ensure that the wind turbines are reliable in stable condition and economical in maintenance cost, the most effective way is to estimate and monitor the performance and operation of the wind turbine. Traditional fault diagnosis methods using multivariate statistical process usually assume the unit only has a single operating condition, so it’s not suitable for multi-regimes. Aiming at this problem, this paper proposed a global performance estimation method of multi-regimes condition based on Gaussian mixture model (GMM). First establish GMM to train the baseline model, cluster the sample data using the similar GMM method, and then calculate the distance between the baseline model and the GMM of sample data by two different methods. The result shows that this method can identify the characteristics of the turbine productivity well, and can detect the abnormality of power curve that is related to incipient fault.

HYBRID IMPLEMENTATION AND PERFORMANCE ANALYSIS FOR HIGH PERFORMANCE COMPUTATION WORKLOAD

Given the need to achieve maximum performance possible, offloading intensive computation workload to GPU is a key to achieve this goal. Offloading most of the workload to GPU may not results in desired performance, so a middle approach is more suitable such as splitting the workload between the CPU and the GPU can be considered as an optimized approach. In this study, we used a popular high performance computation workload which can also be implemented using a hybrid approach in which part of the workload is offloaded to the CPU. We also present a performance estimation method which is verified to estimate performance with in 5% error margin.

삼원 촉매 담체의 확률론적 열피로 성능 평가

A three-way catalyst substrate for domestic passenger car satisfies the design criteria for exhaust gas exchange and pressure drop but does not have satisfactory thermal fatigue performance. Prefracture faults in this three-way catalyst substrate has often been discovered in vehicle repair or vehicle inspection facilities. This paper presents a thermal fatigue performance estimation method for a three-way catalyst substrate using a probabilistic strength reduction factor model. This method is superior to the thermal fatigue performance estimation method for a three-way catalyst substrate that uses a deterministic strength model.

A performance estimation method of Loop Heat Pipe with a wick permeability model considering dry-out of wick pores

In this paper, we propose a practical simulation method for designing Loop Heat Pipe (LHP) which is applied to cooling system for electronic devices. To realize rapid evaluation of cooling performance of LHP, the proposed performance estimation method calculates maximum heat transfer of LHP using 1D thermal-fluid network analysis. However, it is difficult to simulate phase-change of working fluid in LHP accurately with 1D model, since each component of LHP is modeled into a simple 1D network and its detailed shape is not considered enough. Especially, evaporator wick is indispensable component of LHP for determining its maximum heat transfer, and it is required to predict wick dry-out, where working fluid is dried in many pores of wick and LHP does not work as a result. The proposed simulation method introduces a wick pore inactivation model which depends on both input heat and wick pore diameter distribution to consider wick dry-out. The inactivation model applied to calculating wick permeability which determines pressure loss of wick. By fitting the wick permeability model to measured temperature distribution and maximum heat transfer of a LHP prototype for server systems, we show that our model estimates maximum heat transfer within allowable error compared to the experimental value.

Reusing Common Uncoded Experimental Data in Performance Estimation of Different FEC Codes

In this letter, we present a method for performance estimation of forward error correction (FEC) codes using off-line data without data encoding. Only a few hundred thousand uncoded symbols are used to accurately evaluate post-FEC bit error rate of soft FEC codes decodable by the sum-product algorithm at very low error rates, e.g., 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-8</sup> which is only limited by computer performance and simulation time. The method is applicable to both single and concatenated codes. The demonstration is carried out in optical 128-Gb/s polarization division multiplexed experiments with differentially encoded data and 20% redundancy quasi cyclic low-density parity check code.

Múltiplos comprometimentos com o trabalho e suas influências no desempenho: um estudo entre professores do ensino superior no Brasil

O presente trabalho analisa, em docentes do ensino superior, os efeitos dos vínculos com a carreira (comprometimento e entrincheiramento) e com a organização (comprometimento) no seu desempenho. Trata-se de uma pesquisa de corte transversal, envolvendo um survey on line, cujo questionário continha as escalas previamente validadas para medir os vínculos com o trabalho. Para avaliar o desempenho docente foram utilizados dois indicadores: autoavaliação do seu esforço instrucional e uma medida de produção acadêmica. Obteve-se uma amostra de 635 professores de Instituições de Ensino Superior (IES) públicas e privadas. Os dados foram submetidos à análises descritivas e multivariadas. Para identificar os impactos dos vínculos com o trabalho no desempenho foi utilizado o método de estimação por mínimos quadrados parciais (partial least squares - PLS). Nos modelos testados, o entrincheiramento na carreira e o comprometimento organizacional instrumental influenciam negativamente a produção acadêmica dos professores, e o comprometimento com a carreira influencia positivamente o esforço instrucional. Evidências relevantes de como o vínculo do trabalho é um importante preditor do desempenho.

Performance estimation of high performance computing systems with Energy Efficient Ethernet technology

Energy Efficient Ethernet (EEE) is an Ethernet standard for lowering power consumption in commodity network devices. When the load of a link is low, EEE allows the link to turn into a low power mode and therefore can significantly save the power consumption of a network device. EEE is expected to be adopted in high performance computing (HPC) systems a few years later, but the performance impact caused by EEE-enabled in HPC systems is still unknown. To encourage HPC system developers to adopt the EEE technology, it is required for the performance estimation of the non-existing HPC systems that would utilize the EEE technology. This paper presents the performance estimation method for EEE-supported HPC systems, which utilizes a novel performance model we propose. The model with a few profiles for HPC applications allows us to anticipate the performance of the systems not yet realized. The evaluation results show that the proposed model has the significant accuracy and that EEE is still promising for HPC applications.

Identification of potential sites for aquifer storage and recovery (ASR) in coastal areas using ASR performance estimation methods

Performance of freshwater aquifer storage and recovery (ASR) systems in brackish or saline aquifers is negatively affected by lateral flow, density effects, and/or dispersive mixing, causing ambient groundwater to enter ASR wells during recovery. Two recently published ASR performance estimation methods are applied in a Dutch coastal area, characterized by brackish-to-saline groundwater and locally high lateral-flow velocities. ASR performance of existing systems in the study area show good agreement with the predicted performance using the two methods, provided that local vertical anisotropy ratios are limited (<3). Deviations between actual and predicted ASR performance may originate from simplifications in the conceptual model and uncertainties in the hydrogeological and hydrochemical input. As the estimation methods prove suitable to predict ASR performance, feasibility maps are generated for different scales of ASR to identify favorable ASR sites. Successful small-to-medium-scale ASR varies spatially in the study area, emphasizing the relevance of reliable a priori spatial mapping.

Reliability-based optimum seismic design of structures using simplified performance estimation methods

We present an algorithm for the reliability-based seismic design of structures incorporating approximate performance estimation methods and structural optimization. The proposed algorithm allows the automatic design of steel moment-resisting frames using reliability-based criteria and more specifically design criteria based on the mean annual frequency (MAF) that a limit-state is exceeded. Such criteria allow setting constraints with a clear engineering meaning and help to obtain building designs of improved performance and reduced cost. In this work, we propose a simplified approach that allows to quickly calculate the limit-state mean annual frequencies without significant loss of accuracy. More specifically, we use the static-pushover-to-incremental-dynamic-analysis (SPO2IDA) method, which in essence is a R–μ–T relationship with improved properties. SPO2IDA extracts information from the static pushover curve and produces estimates of the limit-state response statistics that are necessary to implement the reliability-based criteria on the limit-state MAF. The optimization problem at hand is solved with a specifically tailored genetic algorithm. A three and a nine-storey steel moment-resisting frame are used to demonstrate the efficiency of the proposed procedure, leading to efficient building designs within reasonable computing time.

Rationale for the choice of the enterprise performance estimation method

The theoretical foundations, scientific and methodological principles of the choice of the enterprise performance estimation method are grounded.Taking into account the basic index of sustainable development, defined through an integral from balance between demand (dependency on purchasing power) and supply (dependency on capital providing), and the relative change of enterprise’s performance indexes for the contiguous intervals (reporting periods), the mathematical generalization of sustainable development indexes for the description of their continuous values is carried out.The methodological significance of transition from the discrete values of indexes of sustainable development to the continuous forms of their expression is grounded. It is marked that partial indexes of sustainable development in a continuous form are partial derivatives by a basic index, and they reflect the rate of change of a basic index depending on the change of indexes that affect the sustainability of the enterprise.The attention is accented on that the known methods of analyzing economic variables by their derivatives can introduce the concept of indexes of sustainable development of the second order, expressing them through the corresponding partial derivatives.It is grounded the necessity of taking into account the criteria of sustainable development indexes inalienability of the second order for the prognostic assessment of the enterprise development dynamics from the standpoint of sustainable development.

Blade Loading and Its Application in the Mean-Line Design of Low Pressure Turbines

In order to minimize the number of iterations to a turbine design, reasonable choices of the key parameters must be made at the preliminary design stage. The choice of blade loading is of particular concern in the low pressure (LP) turbine of civil aero engines, where the use of high-lift blades is widespread. This paper considers how blade loading should be measured, compares the performance of various loss correlations, and explores the impact of blade lift on performance and lapse rates. To these ends, an analytical design study is presented for a repeating-stage, axial-flow LP turbine. It is demonstrated that the long-established Zweifel lift coefficient (Zweifel, 1945, “The Spacing of Turbomachine Blading, Especially with Large Angular Deflection” Brown Boveri Rev., 32(1), pp. 436–444) is flawed because it does not account for the blade camber. As a result the Zweifel coefficient is only meaningful for a fixed set of flow angles and cannot be used as an absolute measure of blade loading. A lift coefficient based on circulation is instead proposed that accounts for the blade curvature and is independent of the flow angles. Various existing profile and secondary loss correlations are examined for their suitability to preliminary design. A largely qualitative comparison demonstrates that the loss correlations based on Ainley and Mathieson (Ainley and Mathieson, 1957, “A Method of Performance Estimation for Axial-Flow Turbines,” ARC Reports and Memoranda No. 2974; Dunham and Came, 1970, “Improvements to the Ainley-Mathieson Method of Turbine Performance Prediction,” Trans. ASME: J. Eng. Gas Turbines Power, July, pp. 252–256; Kacker and Okapuu, 1982, “A Mean Line Performance Method for Axial Flow Turbine Efficiency,” J. Eng. Power, 104, pp. 111–119). are not realistic, while the profile loss model of Coull and Hodson (Coull and Hodson, 2011, “Predicting the Profile Loss of High-Lift Low Pressure Turbines,” J. Turbomach., 134(2), pp. 021002) and the secondary loss model of (Traupel, W, 1977, Thermische Turbomaschinen, Springer-Verlag, Berlin) are arguably the most reasonable. A quantitative comparison with multistage rig data indicates that, together, these methods over-predict lapse rates by around 30%, highlighting the need for improved loss models and a better understanding of the multistage environment. By examining the influence of blade lift across the Smith efficiency chart, the analysis demonstrates that designs with higher flow turning will tend to be less sensitive to increases in blade loading.

методы оценки эффективности инвестиционных решений в общественном секторе экономики

The solution of socially important problems by providing budget investments is a prerequisite for the successful development of a country as a whole as well as of a particular region. In terms of a limited budget there is a problem of projects selection. In the paper basic methods of public sector projects performance estimation (cost — benefit, cost — effectiveness, cost — utility) are compared. It is determined that these methods can help to increase the efficiency of scarce budgetary resources usage. However they cannot be applied in Russia without necessary adjustments since there are market imperfections, high costs of collecting necessary information, and other factors. Thus further development of performance estimation methods in the public sector of economics is needed.

Hybrid Experiential-Heuristic Cognitive Radio Engine Architecture and Implementation

The concept of cognitive radio (CR) focuses on devices that can sense their environment, adapt configuration parameters, and learn from past behaviors. Architectures tend towards simplified decision-making algorithms inspired by human cognition. Initial works defined cognitive engines (CEs) founded on heuristics, such as genetic algorithms (GAs), and case-based reasoning (CBR) experiential learning algorithms. This hybrid architecture enables both long-term learning, faster decisions based on past experience, and capability to still adapt to new environments. This paper details an autonomous implementation of a hybrid CBR-GA CE architecture on a universal serial radio peripheral (USRP) software-defined radio focused on link adaptation. Details include overall process flow, case base structure/retrieval method, estimation approach within the GA, and hardware-software lessons learned. Unique solutions to realizing the concept include mechanisms for combining vector distance and past fitness into an aggregate quantification of similarity. Over-the-air performance under several interference conditions is measured using signal-to-noise ratio, packet error rate, spectral efficiency, and throughput as observable metrics. Results indicate that the CE is successfully able to autonomously change transmit power, modulation/coding, and packet size to maintain the link while a non-cognitive approach loses connectivity. Solutions to existing shortcomings are proposed for improving case-base searching and performance estimation methods.

船外機付き高速滑走艇の推進性能評価法の構築

The purpose of this study is to propose the propulsive performance estimation method for high-speed planing craft with outboard engine. In order to understand the characteristics of propulsion, a fully captive model test with propulsion is carried out. Based on the results, an estimation method taking the self-propulsion factors, which are the changes of hydrodynamic forces acting on hull with lower-hull of outboard engine caused by propeller action, the effective wake fraction and the relative rotative efficiency, is proposed. Using the proposed method, running attitude, thrust (or THP), crank shaft torque (or BHP), maximum forward speed and fuel consumption of a real craft are estimated. As the results, it is found that the effective wake fraction and the relative rotative efficiency of the self-propulsion factors are significant to estimate maximum forward speed of the craft.