Class noise detection based on software metrics and ROC curves

Noise detection for software measurement datasets is a topic of growing interest. The presence of class and attribute noise in software measurement datasets degrades the performance of machine learning-based classifiers, and the identification of these noisy modules improves the overall performance. In this study, we propose a noise detection algorithm based on software metrics threshold values. The threshold values are obtained from the Receiver Operating Characteristic (ROC) analysis. This paper focuses on case studies of five public NASA datasets and details the construction of Naive Bayes-based software fault prediction models both before and after applying the proposed noise detection algorithm. Experimental results show that this noise detection approach is very effective for detecting the class noise and that the performance of fault predictors using a Naive Bayes algorithm with a logNum filter improves if the class labels of identified noisy modules are corrected.     

Constitutive response of calcium‐silicate‐hydrate layers under combined loading

Calcium‐silicate‐hydrate (C‐S‐H) is the main hydration product for ordinary Portland cement (OPC) materials that exhibits a layered structure containing interfaces that controls the system response to shear deformation at the nanometer scale. In this work, we used molecular statics simulations to study the mechanical behavior of an atomistic model of C‐S‐H under combined loading conditions that are typical of structural applications of these materials. Combined loading is implemented by first compressing or stretching the atomistic structure to impose an external hydrostatic pressure, and then loading the system through both heterogeneous and homogeneous shear deformation. By utilizing two different shear methodologies, we were able to isolate the interface behavior from the bulk response. Our results show several qualitative similarities with that of macroscale cementitious materials including pressure sensitivity of the maximum shear strength and strength asymmetry in compression and tension. This indicates that the well‐known cohesive‐frictional behavior of cementitious materials is fundamental to interfaces between C‐S‐H grains at the nanoscale. Comparing differences in our results with nanoindentation experiments motivate future investigations of the effect of C‐S‐H particle size and morphology on strength scaling properties at the mesoscale. These mesoscale model interactions should include the normal‐stress or pressure dependency that we observe.     

Turkish and North American engineering programs: a comparativestudy of curricular emphases on mathematics, basic sciences, humanitiesand social sciences

The state of mathematics, basic sciences, humanities and social sciences in Turkish engineering schools are compared with that in North American schools, as exemplified by electrical engineering. The emphasis on mathematics and basic sciences is strong at Turkish universities relative to North American universities, but the tendency to teach as many courses as possible in the core subject has resulted in a complete neglect of the humanities and social sciences. These differences may have significant long-term implications, in the context of globalization, for both the personal development of engineers and the educational and technological progress of the countries concerned     

Peel and Shear Fracture Characterization of Debonding in FRP Plated Concrete Affected by Moisture

The objective of this paper is to develop a new mechanistic understanding of moisture affected debonding failures in carbon fiber reinforced polymer (CFRP) plated concrete systems by mechanically testing accelerated moisture conditioned mesoscale peel and shear interface fracture specimens. Central to the investigation is the use of interface fracture toughness as the quantification parameter of the CFRP-epoxy-concrete trilayer system, which is considered a bond property, to analyze, compare, and correlate physical observations. Results have shown that fracture toughness of the CFRP bonded concrete systems significantly degrades, and its value becomes asymptotic with increasing moisture ingress. This asymptotic behavior is associated with certain moisture concentration levels as predicted by a three-dimensional moisture diffusion simulation. The generally observed debonding mode by concrete delamination for the dry specimens changes to an epoxy/concrete interface separation mode for the wet specimens. Finite element fracture computation, mixed-mode characterization, and kink criterion implementation synergistically suggest that the interface separation mode is attributed to an interfacial material toughening and an interface weakening mechanism as a consequence of moisture diffusion.     

Encapsulation of anthocyanin with gelatin-alginate carrier by a specially designed ultrasonic encapsulator with adjustable frequency

Anthocyanins are of increasing interest for food applications due to their health benefits. However, their poor stability and susceptibility to unfavorable environmental conditions may limit their application. Microencapsulation offers enhanced stability and controlled release properties. The aim was designing an ultrasonic encapsulator with a variable frequency ultrasonic driver to encapsulate black carrot and mahaleb anthocyanins. First, a double-channel variable frequency and power adjustable ultrasonic driver and atomizer head were designed. The cooled gelation technique was used to encapsulate anthocyanin in an alginate-gelatin complex. Freeze-drying and air-drying techniques were used for drying of microcapsules. Encapsulation parameters were atomization frequency, alginate, and anthocyanin concentrations. The capsules were characterized by encapsulation efficiency, particle diameter, and controlled release rates. Controlled release tests were performed at two different temperatures and pH values. Encapsulation efficiency was 87%–95%, mean diameters were between 69 and 95 μm. Maximum release rates were obtained from freeze-dried mahaleb anthocyanin capsules. Release rates increased with increasing temperature and pH values. In addition, the experimental results showed that the increase in the amount of alginate used in encapsulation decreased the release rate. Moreover, the results proved that the designed encapsulator can be used for encapsulation in fields such as food, pharmaceuticals, polymers, chemistry, and materials.     

面神经损伤后TGF-β的表达与schwann细胞数量变化关系的研究

目的观察兔面神经夹伤后转化生长因子β(transforming growth factor beta,TGF-β)的表达及施万细胞(schwann cells,SCs)数量的变化,了解两者在面神经损伤修复过程中的相互关系及相互作用。方法取20只新西兰大白兔,造成面神经钳夹伤,于伤后1、3、7、14、21d取材分别进行组织学、免疫组化观察。结果 3d时神经夹伤处TGF-β抗原呈阳性反应,施万细胞增多;7d时TGF-β表达呈强阳性反应,为表达高峰,损伤处的施万细胞明显增多;14d时TGF-β表达的量有所减少,施万细胞数量亦无增多趋势;21d时施万细胞数量和TGF-β抗原表达的量均下降。结论 TGF-β参与面神经损伤的病理过程,并与施万细胞数量的变化存在一定的同步性,证实了两者之间存在相互作用。     

A Low-Power Algorithm for Baseband Feedback Used with Frequency Domain Multiplexing

SRON is developing an electronic read-out system for an array of transition edge sensors (TES), which combines the techniques of frequency domain multiplexing (FDM) with base-band feedback (BBFB). An important part of this technique is implemented in digital electronics. This paper describes how a significant reduction of the power consumption of the digital electronics is realized by down-sampling to much lower frequencies using channelization and a poly-phase filter design adapted to BBFB.     

An improved semianalytical method for sensitivity analysis

The semi-analytical method is conveniently used to obtain design sensitivities. However, it may have serious accuracy problems in shape design. In this study, an improved semianalytical method is presented for the accurate computation of shape design sensitivities. The method is based on approximating the flexibility matrix by means of von Neumann series. In numerical examples, two cases for which the standard semianalytical method fails are considered. It is demonstrated that the sensitivities can be obtained very accurately by the improved method proposed.