Occupancy‐based decision support system for building management: From automation to end‐user persuasion

In this paper, an intelligent occupancy‐based, automated building control system is initially introduced, which has the capability of reducing energy consumption while respecting the occupants' comfort and actions inside building areas. Data stemming from a multisensorial network is combined with implicitly extracted information, since no direct feedback is expected by the users, towards unsupervised monitoring and control of building operation. However, due to significantly higher costs of actuating equipment and the reluctance that some end users show in accepting fully automated solutions, a new hybrid approach is conceptualized and presented; the automated decision support system is supplemented with a persuasion mechanism aimed at increasing energy savings, through raising user awareness. The persuasive methodology employs a continuous feedback mechanism in order to select the optimal incentive strategy by taking into account user success rates, in terms of requested actions, as well as available mechanisms, and daily harassment.     

Comparative study of toughness between the AH 40 fatigue crack arrester steel and its weld metal in the case of robotic metal-cored arc welding

The current investigation aims to scrutinize the impact and fracture toughness of the AH 40 fatigue crack arrester (FCA) steel and its weld metal, when welded with the metal-cored arc welding technique (MCAW). Initially, macroscopic observation and microstructural characterization were carried out in the areas of interest. Subsequently, the impact toughness was determined with the use of the Charpy V-notch test (CVN) at various temperatures, while the values of the absorbed energy (KV), the percentage of shear fracture (PSF), and the lateral expansion (LE) were recorded. Moreover, the ruptured surfaces were examined with a scanning electron microscope (SEM). Finally, the crack tip opening displacement (δ) parameter was estimated at room temperature by fracture toughness testing. The obtained data led to the quantification of the toughness parameters, when dynamic or quasistatic load is applied, while the combined effect of several factors to the degradation of the weld metal toughness was elucidated. The ductile to brittle transition curve and the crack tip opening displacement in the weld metal appeared to be lower than inside the unaffected material. Nevertheless, fracture toughness properties were evaluated within acceptable limits in all cases.     

Efficient frequency-doubling in a poled PVDF copolymer guest/host composite

We describe the linear and nonlinear properties of a new polymer composite, which uses a ferroelectric PVDF copolymer host in which an optically nonlinear low-molecularweight guest is dissolved and subsequently aligned using a room-temperature poling process. We have measured the frequency-doubling coefficient d33 of these poled composites at 1-064/mi to be as high as 2-6 × 10?12m/V. In addition, we have shown that this material may be formed into waveguiding structures with an acceptable optical loss (?5dB/cm), as is needed in many signal processing systems.     

CFD simulation of magnetorheological fluid journal bearings

Magnetorheological fluid journal bearing can be controlled by a steady magnetic field doing that very effective for attenuating and controlling the performance of the rotor bearing systems.An integrated simulation study, of a magnetorheological (MRF) fluid journal bearing, via computational fluid dynamics (CFD) and finite element method (FEM) is presented in this paper. The journal bearing characteristics such as, eccentricity, attitude angle, oil flow and friction coefficients are calculated and presented as functions of the magnetic field, and L/D bearing ratios.A specific procedure in order to simulate an MRF bearing operated in high eccentricity ratios is also presented and the meshing requirements are discussed.     

How to improve the peer review method: Free-selection vs assigned-pair protocol evaluated in a computer networking course

This study provides field research evidence on the efficiency of a “free-selection” peer review assignment protocol as compared to the typically implemented “assigned-pair” protocol. The study employed 54 sophomore students who were randomly assigned into three groups: Assigned-Pair (AP) (the teacher assigns student works for review to student pairs), Free-Selection (FS) (students are allowed to freely explore and select peer work for review), and No Review (NR) (control group). AP and FS student groups studied and reviewed peer work in the domain of Computer Networking, supported by a web-based environment designed to facilitate the two peer review protocols. Our results indicate that students following the Free Selection protocol demonstrate (a) better domain learning outcomes, and (b) better reviewer skills, compared to the AP condition. Overall, the study analyzes the benefits and shortcomings of the FS vs AP review assignment protocol, providing evidence that the FS condition can be multiply beneficial to students who engage in peer review activities.     

Detecting Collaborations in Text Comparing the Authors' Rhetorical Language Choices in The Federalist Papers

In author attribution studies function words or lexical measures areoften used to differentiate the authors' textual fingerprints. Thesestudies can be thought of as quantifying the texts, representing thetext with measured variables that stand for specific textual features.The resulting quantifications, while proven useful for statisticallydifferentiating among the texts, bear no resemblance to the understanding a human reader – even an astute one – would develop whilereading the texts. In this paper we present an attribution study that,instead, characterizes the texts according to the representationallanguage choices of the authors, similar to a way we believe close humanreaders come to know a text and distinguish its rhetorical purpose. Fromour automated quantification of The Federalist papers, it isclear why human readers find it impossible to distinguish the authorshipof the disputed papers. Our findings suggest that changes occur in theprocesses of rhetorical invention when undertaken in collaborativesituations. This points to a need to re-evaluate the premise ofautonomous authorship that has informed attribution studies of The Federalist case.     

Nanomechanical properties of friction stir welded AA6082-T6 aluminum alloy

Lightweight alloys are of major concern, due to their functionality and applications in transport and industry applications. Friction stir welding (FSW) is a solid-state welding process for joining aluminum and other metallic alloys and has been employed in aerospace, rail, automotive and marine industries. Compared to the conventional welding techniques, FSW produces joints which do not exhibit defects caused by melting. The objective of the present study is to investigate the surface hardness (H) and elastic modulus (E) in friction stir welded aluminum alloy AA6082-T6. The findings of the present study reveal that the welding process softens the material, since the weld nugget is the region where the most deformations are recorded (dynamic recrystallization, production of an extremely fine, equiaxial structure), confirmed by optical microscopy and reduced nanomechanical properties in the welding zone. A yield-type pop-in occurs upon low loading and represents the start of phase transformation, which is monitored through a gradual slope change of the load-displacement curve. Significant pile-up is recorded during nanoindentation of the alloy through SPM imaging.     

Exploiting semantic proximities for content search over p2p networks

In this paper, we address the issue of content search over peer-to peer networks. We use the concept of semantic proximity that exploits the commonalities of interests exhibited among peer users so as to decompose the network into semantic clusters. We initially define search entropy, as a metric indicating the average number of packets required to locate the requested content. Then, spectral clustering is used to organize the peer nodes into semantic clusters so that (a) the probability that a node locates content within its own cluster is maximized, while simultaneously; (b) the respective probability of finding this content outside this cluster is minimized. The proposed semantic partitioning algorithm is then extended into a hierarchical two-tier scheme, in which practical issues arising for the deployment of a peer-to-peer (p2p) application can be more easily addressed. After the system has been initialized, a dynamic algorithm places new users that join the p2p network into appropriately selected clusters and also handles peer departures without the need for matrix eigen decomposition process which is necessary for the assessment of the initial static partitioning. Our experimental results validate that (a) our static partitioning outperforms traditional and novel search techniques and (b) our dynamic algorithm is able to efficiently track the system’s progression maintaining the search entropy close to the initially assessed levels.     

Image registration based on lifting process: an application to digital subtraction radiography.

In this paper, a digital subtraction radiology scheme is presented based on a new method for the automatic registration of dental radiographs acquired with or without rigorous a priori standardization. The scheme is comprised of an automatic registration method and a subtraction process. The proposed registration method can be considered as an object-based registration method without imposing the prerequisite of image segmentation in order to detect the boundary of the objects of interest or the automatic detection of matching landmarks. This is achieved by augmenting the dimensionality of the problem from two-dimensional gray-level matching to three-dimensional surface matching using the process of lifting in combination with a surface-matching technique. The pseudo three-dimensional affine transformation that matches the lifted images incorporates advantageous characteristics including spatial alignment of the surfaces, anisotropic correction of brightness/contrast differences, and stable convergence of the similarity function to its optimal value. The performance of the proposed automatic registration method is assessed against a manual method based on the projective transformation. The qualitative and quantitative assessments of the experiments have shown advantageous performance of the proposed automatic registration method against the manual one. Finally, the proposed registration method has been further improved in terms of execution time by the implementation of a surface decimation process.