Evaluation of the relative differences in building energy simulation results

Building energy modeling,also known as building energy simulation,has developed rapidly in recent years and plays a crucial role in building life-cycle analysis.It can be employed in the design phase to predict the energy consumption of different design schemes and evaluate various control and retrofitting measures at the operation stage.In such simulations,it is commonly understood and accepted that the simulated relative differences are more reliable than the predictions of absolute energy results.However,whether this common understanding is true is yet to be thoroughly investigated.In this study,we investigate the simulated relative differences and the extent to which they are affected by the degree of model input deviation.Simulation and Monte Carlo approaches are adopted for the analysis.The results indicate that the simulated relative differences are not as reliable as expected,and the outputs strongly depend on the degree of the model input deviation.When the degree of deviation is less than 15%or the model inputs are within reasonable ranges,the simulated relative differences match the baseline obtained using Monte Carlo simulations.Moreover,the model’s error indicators meet the requirements of the ASHRAE Guideline 14–2014 when the degree of input deviation is below 15%.

Hard life for sons in the nest?Sex-dependent offspring mortality in Great Tits in urban and forest areas

Sex-biased mortality can occur in birds during development,for example due to sexual differences in energy requirement and/or environmental sensitivity,or the effects of sex hormones or sex differences in the expression of mutations linked to sex chromosomes.The extent of sex-bias in mortality may also be related to environmental conditions that influence offspring development and survival.Urban areas often provide poorer conditions for nestling development resulting in higher offspring mortality compared to natural areas,which may accelerate sex differences in offspring mortality in cities.To test this hypothesis,we examined the sex ratio of dead offspring in Great Tits(Parus major),using 427 samples of unhatched eggs and dead nestlings collected in two urban and two forest sites between 2013 and 2019.The ratio of males in the whole sample of dead offspring(56.9%)was significantly higher than expected by an 1:1 ratio,and the strongest sex biases were detected in urban areas(57.6%males)and in young nestlings(<14 days old,59.0%males).However,the sex ratios of dead offspring did not differ significantly among study sites and between offspring developmental stages.29.3%of unhatched eggs contained a visible embryo,and the proportion of embryo-containing unhatched eggs did not differ significantly between urban and forest study sites.These results suggest male-biased offspring mortality in Great Tits,and highlight the need of large datasets to detect subtle differences between habitats and developmental stages.

A review of the influencing factors on teleseismic traveltime tomography

Teleseismic traveltime tomography is an important tool for investigating the crust and mantle structure of the Earth.The imaging quality of teleseismic traveltime tomography is affected by many factors,such as mantle heterogeneities,source uncertainties and random noise.Many previous studies have investigated these factors separately.An integral study of these factors is absent.To provide some guidelines for teleseismic traveltime tomography,we discussed four main influencing factors:the method for measuring relative traveltime differences,the presence of mantle heterogeneities outside the imaging domain,station spacing and uncertainties in teleseismic event hypocenters.Four conclusions can be drawn based on our analysis.(1)Comparing two methods,i.e.,measuring the traveltime difference between two adjacent stations(M1)and subtracting the average traveltime of all stations from the traveltime of one station(M2),reveals that both M1 and M2 can well image the main structures;while M1 is able to achieve a slightly higher resolution than M2;M2 has the advantage of imaging long wavelength structures.In practical teleseismic traveltime tomography,better tomography results can be achieved by a two-step inversion method.(2)Global mantle heterogeneities can cause large traveltime residuals(up to about 0.55 s),which leads to evident imaging artifacts.(3)The tomographic accuracy and resolution of M1 decrease with increasing station spacing when measuring the relative traveltime difference between two adjacent stations.(4)The traveltime anomalies caused by the source uncertainties are generally less than 0.2 s,and the impact of source uncertainties is negligible.

Spatial variability and temporal stability of actual evapotranspiration on a hillslope of the Chinese Loess Plateau

Actual evapotranspiration(ETa)is a key component of water balance.This study aimed to investigate the spatial variability and time stability of ETa along a hillslope and to analyze the key factors that control the spatiotemporal variability of ETa.The potential evaporation,surface runoff and 0–480 cm soil water profile were measured along a 243 m long transect on a hillslope of the Loess Plateau during the normal(2015)and wet(2016)water years.ETa was calculated using water balance equation.Results indicated that increasing precipitation during the wet water year did not alter the spatial pattern of ETa along the hillslope;time stability analysis showed that a location with high time stability of ETa could be used to estimate the mean ETa of the hillslope.Time stability of ETa was positively correlated with elevation(P<0.05),indicating that,on a hillslope in a semi-arid area,elevation was the primary factor influencing the time stability of ETa.

APPROACH FOR LAYOUT OPTIMIZATION OF TRUSS STRUCTURES WITH DISCRETE VARIABLES UNDER DYNAMIC STRESS, DISPLACEMENT AND STABILITY CONSTRAINTS

A mathematical model was developed for layout optimization of truss structures with discrete variables subjected to dynamic stress, dynamic displacement and dynamic stability constraints. By using the quasi-static method, the mathematical model of structure optimization under dynamic stress, dynamic displacement and dynamic stability constraints were transformed into one subjected to static stress, displacement and stability constraints. The optimization procedures include two levels, i.e., the topology optimization and the shape optimization. In each level, the comprehensive algorithm was used and the relative difference quotients of two kinds of variables were used to search the optimum solution. A comparison between the optimum results of model with stability constraints and the optimum results of model without stability constraint was given. And that shows the stability constraints have a great effect on the optimum solutions.

Performance of Dexcom G5 and FreeStyle Libre sensors tested simultaneously in people with type 1 or 2 diabetes and advanced chronic kidney disease

BACKGROUND Advanced chronic kidney disease(CKD) is a common complication for people with type 1 and 2 diabetes and can often lead to glucose instability. Continuous glucose monitoring(CGM) helps users monitor and stabilize their glucose levels. To date, CGM and intermittent scanning CGM are only approved for people with diabetes but not for those with advanced CKD.AIM To compare the performance of Dexcom G5 and FreeStyle Libre sensors in adults with type 1 or 2 diabetes and advanced CKD.METHODS This was a non-randomized clinical trial that took place in two outpatient clinics in western Sweden. All patients with type 1 or 2 diabetes and an estimated glomerular filtration rate(eGFR) of < 30 mL/min per 1.73 m^(2) were invited to participate. Forty patients(full analysis set = 33) carried the Dexcom G5 sensor for 7 d and FreeStyle Libre sensor for 14 d simultaneously. For referencing capillary blood glucose(SMBG) was measured with a high accuracy glucose meter(HemoCue®) during the study period. At the end of the study, all patients were asked to answer a questionnaire on their experience using the sensors.RESULTS The mean age was 64.1(range 41-77) years, hemoglobin A1 c was 7.0% [standard deviation(SD) 3.2], and diabetes duration was 28.5(SD 14.7) years. A total of 27.5% of the study population was on hemodialysis and 22.5% on peritoneal dialysis. The mean absolute relative difference for Dexcom G5 vs SMBG was significantly lower than that for FreeStyle Libre vs SMBG [15.2%(SD 12.2) vs 20.9%(SD 8.6)], with a mean difference of 5.72 [95% confidence interval(CI): 2.11-9.32;P = 0.0036]. The mean absolute difference was also significantly lower for Dexcom G5 than for FreeStyle Libre, 1.21 mmol/L(SD 0.78) and 1.76 mmol/L(SD 0.78), with a mean diffrenec of 0.55(95%CI: 0.27-0.83;P = 0.0004).The mean difference(MD) was-0.107 mmol/L and-1.10 mmol/L(P = 0.0002), respectively. In all, 66% of FreeStyle Libre values were in the no risk zone on the surveillance error grid compared to 82% of Dexcom G5 values.CONCLUSION Dexcom G5 produces more accurate sensor values than FreeStyle Libre in people with diabetes and advanced CKD and is likely safe to be used by those with advanced CKD.

Localization and Degree of Damage Based on Relative Curvature Difference and Frequency Perturbation

This study proposed a damage identification method compared with the existing ones,based on relative curvature difference and frequency perturbation theory,showing sensitivity to local damage by changes in the curvature mode and high recognition accuracy of frequencies.Considering the relative curvature difference as a damage index,numerical simulation is used for a simply supported beam under single and multiple damage conditions for different damage degrees.The damage is located according to the curvature mode curves,and the damage degree is qualitatively determined.Based on the perturbation theory,the damage equations are established by the changes between frequencies before and after damage,and the damage localization and degree are verified and determined.Effectiveness of the proposed method for identifying damage at different conditions is numerically investigated.This method potentially promotes the development of damage identification of beam structures.

A UNIVERSAL APPROACH FOR CONTINUOUS OR DISCRETE NONLINEAR PROGRAMMINGS WITH MULTIPLE VARIABLES AND CONSTRAINTS

A universal numerical approach for nonlinear mathematic programming problems is presented with an application of ratios of first-order differentials/differences of objective functions to constraint functions with respect to design variables. This approach can be efficiently used to solve continuous and, in particular, discrete programmings with arbitrary design variables and constraints. As a search method, this approach requires only computations of the functions and their partial derivatives or differences with respect to design variables, rather than any solution of mathematic equations. The present approach has been applied on many numerical examples as well as on some classical operational problems such as one-dimensional and two-dimensional knap-sack problems, one-dimensional and two-dimensional resource-distribution problems, problems of working reliability of composite systems and loading problems of machine, and more efficient and reliable solutions are obtained than traditional methods. The present approach can be used without limitation of modeling scales of the problem. Optimum solutions can be guaranteed as long as the objective function, constraint functions and their First-order derivatives/differences exist in the feasible domain or feasible set. There are no failures of convergence and instability when this approach is adopted.

Relation of loudness to loudness just noticeable difference of tone

A relation of loudness to loudness just noticeable difference (JND) is derived based on signal detection theory and the hypothesis that loudness is the nerve spike count in the duration of T, and the spike rate distribution of stable tonal stimulus is a stable normal stochastic process. The relation suggests that ratio of loudness JND to loudness of tone is independent of intensity, which can explain well experimental results about the relation of intensity JND to intensity of tone, especially those that could not be explained before such as the Weber fraction hump at the moderate level and the near miss to Weber's law.

Relations of intensity just noticeable difference to intensity of tonal bursts with various durations

The relations of intensity Just Noticeable Difference (JND) to intensity for tone bursts maybe,depend on signal durations according to Jont B.Allen's [J. Acoust. Soc. Am. 102 3, 1997, 3628--3646.]. The intensity just noticeable differences for tone bursts with durations of 1 ms, 10 ms, 100 ms, 1000 ms, 5000 ms and 10000 ms were measured at different intensity levels of 20 dB, 30 dB, 40 dB, 50 dB, 60 dB, 70 dB, 80 dB, 90 dB, 100 dB. The data show that variance of Weber fraction (△I/I) with intensity is distinct from Riesz's result and SPIN theory, and that the relations between Weber fraction and intensity for signals of different durations are similar in spite of Weber fraction decreasing to asymptote with signal duration increasing. This means the difference of pulse measurement of intensity JND from Riesz's result and SPIN theory does not arise from the limited signal duration of pulse method and provides new cue for hearing research.

Study of broadband THz time-domain spectroscopy at different relative humidity levels

Two detection techniques of broadband terahertz（THz）time-domain spectroscopy-THz air-biased coherent detection（THz-ABCD;from 0.3 to 14 THz）and electro-optical（EO）detection（from 0.3 to 7 THz）-are both performed at several different relative humidity levels.The THz power exponentially decays with the increase in relative humidity.The dynamic range of the main pulse in the time domain linearly decreases as the relative humidity increases from 0%to 40%,and linear fittings show that the slopes are-0.017 and-0.019 for THz-ABCD and EO detection,respectively.Because of the multiple reflections caused by the crystal in the common EO detection,THz-ABCD has better spectral resolution（17 GHz）than that of EO detection（170 GHz）.The spectrum of water vapor absorption measured by THz-ABCD is also compared with that measured by the Fourier transform infrared spectroscopy（FTIR）.

Constructions of optimal variable-weight OOCs via quadratic residues

Variable-weight optical orthogonal code （OOC） was introduced by G. C. Yang [IEEE Trans. Commun., 1996, 44： 47-55] for multimedia optical CDMA systems with multiple quality of service （QoS） requirements. In this paper, seven new infinite classes of optimal （v, {3,4,6}, 1, Q）-OOCs are constructed.

Constructions for Anonymous Secret Sharing Schemes Using Combinatorial Designs

In an anonymous secret sharing scheme the secret can be reconstructed without knowledge of which participants hold which shares. In this paper some constructions of anonymous secret sharing schemes with 2 thresholds by using combinatorial designs are given. Let v（t, w, q） denote the minimum size of the set of shares of a perfect anonymous （t, w） threshold secret sharing scheme with q secrets. In this paper we prove that v（t, w, q） - Θ（q） if t and w are fixed and that the lower bound of the size of the set of shares in [4] is not optimal under certain condition.

Correlation between solubility parameters and recovery of phenolic compounds from fast pyrolysis bio-oil by diesel extraction

Fast pyrolysis bio-oils(fpBO)were extracted with two alternative commercial transportation fuels,hydrocarbon diesel and bio-diesel.The extraction of fpBO with commercial diesel fuel provided a yield of 4.3 wt%,but the yield increased significantly to 26.6 wt%when bio-diesel was the extractant.The molecular weight of fpBO before and after extraction were consistent with the loss of a more soluble,low molecular weight fraction from the crude fpBO.The relative energy difference(RED),based on the Hansen solubility parameter(HSP),is used to examine the extraction efficiency of specific compounds in the two different‘solvents’.Differences in the RED values could be used to rationalize differences in the partitioning of common fpBO phenolics.