Registration using natural features for augmented reality systems

Registration is one of the most difficult problems in augmented reality (AR) systems. In this paper, a simple registration method using natural features based on the projective reconstruction technique is proposed. This method consists of two steps: embedding and rendering. Embedding involves specifying four points to build the world coordinate system on which a virtual object will be superimposed. In rendering, the Kanade-Lucas-Tomasi (KLT) feature tracker is used to track the natural feature correspondences in the live video. The natural features that have been tracked are used to estimate the corresponding projective matrix in the image sequence. Next, the projective reconstruction technique is used to transfer the four specified points to compute the registration matrix for augmentation. This paper also proposes a robust method for estimating the projective matrix, where the natural features that have been tracked are normalized (translation and scaling) and used as the input data. The estimated projective matrix will be used as an initial estimate for a nonlinear optimization method that minimizes the actual residual errors based on the Levenberg-Marquardt (LM) minimization method, thus making the results more robust and stable. The proposed registration method has three major advantages: 1) It is simple, as no predefined fiducials or markers are used for registration for either indoor and outdoor AR applications. 2) It is robust, because it remains effective as long as at least six natural features are tracked during the entire augmentation, and the existence of the corresponding projective matrices in the live video is guaranteed. Meanwhile, the robust method to estimate the projective matrix can obtain stable results even when there are some outliers during the tracking process. 3) Virtual objects can still be superimposed on the specified areas, even if some parts of the areas are occluded during the entire process. Some indoor and outdoor experiments have been conducted to validate the performance of this proposed method.     

Two methods of natural family planning

I read with interest the recent article by Wade and associates, "A randomized prospective study of the use-effectiveness of 2 methods of natural family planning: an interim report" (134: 628, 1979). In reference to the study of the ovulation method, the authors noted that abstinence begins on the 1st day of mucus secretion and continues until the evening of the 4th day beyond the peak or maximal mucus secretion. In the ovulation method, the peak symptom is not the same as maximal mucus secretion as was indicated in the paper. The peak symptom is defined as the last day of the mucus discharge that is clear and/or stretchy and/or lubricative. In the definition of peak symptom, the amount of mucus discharge is not specifically important and may often be misleading. I had the opportunity to do a site visit at this study at the request of the National Institutes of Health while the study was in progress. I analyzed several pregnancies which occurred in users of this ovulation method. Some of the pregnancies occurred as the result of poor teaching of the concept of peak symptom. In the ovulation method, proper understanding and teaching of that concept are essential to the measurement of its effectiveness. Noticeably missing from this interim report was any discussion of the quality control procedures which were utilized to guarantee a high-quality educational service to the people entered into the study. While the authors claim that the methods were taught by professional teachers, these teachers were actually women who had previously used the method and/or had formalized training in teaching the method. Simple use of either of the methods certainly does not qualify an individual to teach natural family planning. For those with formalized teaching, such training should have been outlined since judgment on the effectiveness of the teaching cannot be made; such a judgment is essential to the proper analysis of results. Finally, while the study claims to be a use-effectiveness study, it is rather a modified version of extended use-effectiveness. No objective definition of "user failure" is provided. One cannot ascertain how many pregnancies were related to poor teaching, nor can one tell how many occurred as the result of the couples' last minute exercise of their freedom to use their fertility. The use-effectiveness of the 2 methods under study as a means to achieve a pregnancy have been ignored. In doing so, the investigators have ignored use-effectiveness reality.     

Relationship between a behavioral and several psychometric measures of test anxiety

Behavioral time-sampling was compared with various paper-and-pencil, self-report measures of test anxiety in an examination of the utility of the behavioral measure as an in situo index of test anxiety. The behavioral measure was significantly and positively correlated 0.45 with a paper-and pencil, self-report measure of "facilitative" test anxiety but not with measures of "debilitative" test anxiety (r = -0.15) or general anxiety (r = -0.33) for 12 males and 21 female undergraduates.     

General Liability Insurance Coverage for Mold Claims

Although humans and mold have coexisted for centuries, the effects of mold on health and property have recently received considerable attention. Members of the construction industry and commercial property owners are, with increasing frequency, finding themselves defending claims of property damage or personal injury due to indoor mold growth. These designers, builders, and property owners frequently turn to their general liability insurance carriers for defense and indemnification without having a full understanding of the protections afforded by their commercial general liability policies. This article provides an introduction to the typical coverages and exclusions applicable to mold related claims submitted for general liability coverage. This article also discusses maximizing the potential for coverage by notifying and cooperating with one’s insurer and provides guidance on the avoidance of indoor mold growth and claims. Questions concerning the meaning and effect of particular insurance policy provisions and the availability of additional or alternative coverages should be directed to one’s insurance professional or coverage attorney.     

Feature-based design in a distributed and collaborative environment

In this paper, a client/server framework has been developed to enable a dispersed team to accomplish a feature-based design task collaboratively. A manipulation client+modelling server infrastructure has been proposed to facilitate consistent primary information modelling for multiple users and adaptability of the system. Based on feature-to-feature relationships, a distributed feature manipulation mechanism has been proposed to filter the varied information of a working part during a co-design activity to avoid unnecessary re-transferring of the complete large-size CAD files each time when any interactive operation is imposed on the model by a client. In the distributed environment, a design task and the engaged clients are organised and connected through working sessions generated and maintained dynamically with a collaborative server. The environment is open to downstream manufacturing analysis modules to achieve distributed concurrent engineering.     

Hybrid Approach to Modeling the Process of Convective Radiative Heat and Mass Transfer in Closed Differentially Heated Cavities

Journal of Engineering Physics and Thermophysics - A hybrid model has been developed for the analysis of the process of combined mass and heat transfer in closed rectangular cavities under the...     

Human Endothelial Progenitor Cells Protect the Kidney against Ischemia-Reperfusion Injury via the NLRP3 Inflammasome in Mice

Ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury (AKI) and progression to chronic kidney disease (CKD). However, no effective therapeutic intervention has been established for ischemic AKI. Endothelial progenitor cells (EPCs) have major roles in the maintenance of vascular integrity and the repair of endothelial damage; they also serve as therapeutic agents in various kidney diseases. Thus, we examined whether EPCs have a renoprotective effect in an IRI mouse model. Mice were assigned to sham, EPC, IRI-only, and EPC-treated IRI groups. EPCs originating from human peripheral blood were cultured. The EPCs were administered 5 min before reperfusion, and all mice were killed 72 h after IRI. Blood urea nitrogen, serum creatinine, and tissue injury were significantly increased in IRI mice; EPCs significantly improved the manifestations of IRI. Apoptotic cell death and oxidative stress were significantly reduced in EPC-treated IRI mice. Administration of EPCs decreased the expression levels of NLRP3, cleaved caspase-1, p-NF-κB, and p-p38. Furthermore, the expression levels of F4/80, ICAM-1, RORγt, and IL-17RA were significantly reduced in EPC-treated IRI mice. Finally, the levels of EMT-associated factors (TGF-β, α-SMA, Snail, and Twist) were significantly reduced in EPC-treated IRI mice. This study shows that inflammasome-mediated inflammation accompanied by immune modulation and fibrosis is a potential target of EPCs as a treatment for IRI-induced AKI and the prevention of progression to CKD.     

Back-end soft and hard defect monitoring using a single test chip

The objective of this paper is to present a mixed test structure designed to characterize yield losses due to hard defect and back-end process variation (PV) at die and wafer level. A brief overview of the structure, designed using a ST-Microelectronics’ 130 nm technology, is given. This structure is based on a SRAM memory array for detecting hard defects. Moreover each memory cell can be configured in the Ring Oscillator (RO) mode for back-end PV characterization. The structure is tested in both modes (SRAM, RO) using a single test flow. The test data analysis method is presented and applied to experimental results to confirm the ability of the structure to monitor PV and defect density.     

Respiratory symptoms and pulmonary function in coal miners: looking into the effects of simple pneumoconiosis

Most soil quality guidelines do not distinguish among the various forms of metals in soils; insoluble, nonreactive, and nonbioavailable forms are deemed as hazardous as highly soluble, reactive, and toxic forms. The objective of this study was to better understand the long-term effects of copper on microorganisms in relation to its chemical speciation in the soil environment. Carbon mineralization processes and the global structure of different microbial communities (fungi, eubacteria, actinomycetes) are still affected after more than 50 years of copper contamination in 20 soils sampled from two different agricultural sites. The microbial respiration lag period (LP) preceding the beginning of mineralization process increases with the level of soil copper contamination and is not significantly affected by other environmental factors such as soil pH and soil organic matter (SOM) content. The total copper concentration showed the best correlation with the LP when each site is considered separately. However, when considering the whole set of data, soil solution free Cu2+ activity (pCu2+) is the best predictor of Cu toxicity determined by LP (quite likely because pCu2+ integrates the soil physicochemical variability). The maximum mineralization rate (MMR), even if well correlated with the pCu2+, appears not to be a good biomonitor of copper contamination in soils since it is highly sensitive to soil characteristics such as SOM content. This study emphasizes the importance of the physicochemical properties of the environment on soil heavy metal toxicity and on soil toxicological measurements. These properties must be characterized in soil toxicological studies with respect to (1) their interactions with heavy metals, and (2) their direct impact on the selected biological test. The measurement of pCu2+ to characterize the level of soil contamination and of lag period as a bioindicator of metal effects in the soil are recognized as useful tools for the evaluation of the biological quality of soils.