Utilization of ubiquitous computing for construction AR technology

Based on the investigation of the characteristics of construction sites in terms of AR technology suitability, this paper introduces the application of a new framework of ubiquitous augmented reality (AR) technology (titled U-AR) to a construction site where high mobility, free from occlusion, good accuracy, and expandability into large scale applications play a key role in meeting the practical requirements. U-AR is intended to enhance accessibility to the distributed networks that provide a gateway between a physical construction site and the digital information of AR. To illustrate the U-AR system, the detailed schematic architecture of the AR display technique, motion tracking method, and server implementation is discussed throughout the preliminary studies. The proposed architectures of U-AR present a direction of what technologies regarding display, tracker, and server should be focused for the development of the compelling U-AR. It is found that the proposed U-AR is expected to be the best suitable technology to provide AR-based visual information in construction sites.     

A method for evaluation of an optical image stabilizer in an image sensor module

A figure of merit called the image clarity index is proposed for quantifying the performance of an optical image stabilizer (OIS) subjected to hand jitter. The image clarity index is defined as the slope angle of the normalized edge spread intensity of a captured image. A two-dimensional map of the index can offer clues as to the design limit on shake angle and frequency. Because of its relative simplicity over the existing metrics such as the modulation transfer function, the proposed index is especially suitable for summary evaluation of OISs and rapid benchmarking of OIS-equipped image sensor modules.     

Phase-only adaptive Processing based on a direct data domain least squares approach using the conjugate gradient method

Generally, adaptive antenna arrays operate by changing the complex adaptive weights consisting of both magnitudes and phases applied at each of the antenna elements. However, it is easier to require the adaptive weights have only phase variation with a fixed magnitude at each of the antenna elements. Hence, This work addresses the phase only adaptive systems whose weights have a fixed magnitude through a new phase only adaptive method based on a direct data domain least squares approach (D/sup 3/LS), which utilize only a single snapshot of the data for adaptive processing.     

Miniaturized lead sensor based on lead-specific DNAzyme in a nanocapillary interconnected microfluidic device

A miniaturized lead sensor has been developed by combining a lead-specific DNAzyme with a microfabricated device containing a network of microfluidic channels that are fluidically coupled via a nanocapillary array interconnect. A DNAzyme construct, selective for cleavage in the presence of Pb2+ and derivatized with fluorophore (quencher) at the 5' (3') end of the substrate and enzyme strands, respectively, forms a molecular beacon that is used as the recognition element. The nanocapillary array membrane interconnect is used to manipulate fluid flows and deliver the small-volume sample to the beacon in a spatially confined detection window where the DNAzyme is interrogated using laser-induced fluorescence detection. A transformed log plot of the fluorescent signal exhibits a linear response (r2 = 0.982) over a Pb2+ concentration range of 0.1 - 100 microM, and a detection limit of 11 nM. The sensor has been applied to the determination of Pb2+ in an electroplating sludge reference material, the result agreeing with the certified value within 4.9%. Quantitative measurement of Pb2+ in this complex sample demonstrates the selectivity of this sensor scheme and points favorably to the application of such technologies to analysis of environmental samples. The unique combination of a DNAzyme with a microfluidic-nanofluidic hybrid device makes it possible to change the DNAzyme to select for other compounds of interest, and to incorporate multiple sensing systems within a single device for greater flexibility. This work represents the initial steps toward creation of a robust field sensor for lead in groundwater or drinking water.     

A study on conformational changes by electron charges in viologen single molecules by using STM

The topography of self-assembled viologen derivatives (VC(8)SH, VC(10)SH, HSC(8)VC(8)SH, and HSC(10)VC(10)SH) molecules on an octanethiol (C(8)) self-assembled monolayer (SAM) modified gold surface was measured using ultrahigh-vacuum scanning tunneling microscopy (UHV-STM). We demonstrate here a novel matrix SAM appropriate for isolation of the viologen molecules. The C(8) was used for a matrix SAM, in which the VC(8)SH, VC(10)SH, HSC(8)VC(8)SH, and HSC(10)VC(10)SH were inserted at molecular lattice defects. The isolated single molecules of viologen derivatives inserted in the matrix SAM were observed as protrusions in STM topography using a constant current mode. We measured the topographic heights (VC(8)SH: 1.53nm, VC(10)SH: 2.01nm, HSC(8)VC(8)SH: 2.71nm, and HSC(10)VC(10)SH: 3.3nm) of the molecular protrusions using STM. Also, changes in the central axis of viologen molecules were observed as VC(8)SH (0.5-0.73nm), VC(10)SH (0.4-0.74nm), HSC(8)VC(8)SH (0.67-0.84nm), and HSC(10)VC(10)SH (0.67-0.99nm), respectively.     

Prediction of surface temperature rise of ultrasonic diagnostic array transducers

Temperature rise at the surface of an ultrasound transducer used for diagnostic imaging is an important factor in patient safety and regulatory compliance. This paper presents a semianalytical model that is derived from first principles of heat transfer and is simple enough to be implemented in a commercial ultrasound scanner for real-time forecasting of transducer surface temperature. For modeling purposes, one-dimensional array transducers radiating into still air are considered. Promising experimental verification data are shown and practical implementation benefits of the model for thermal design and management of ultrasonic array transducers are discussed. In particular, the reduction in the amount of thermal characterization data required, compared to empirical models, shows promise.     

Cost-Benefit Analysis of Embedded Sensor System for Construction Materials Tracking

Tracking and monitoring the location of materials on a construction job site is an important, yet commonly overlooked aspect of field data acquisition because timely information about the status of materials, equipment, tools, and labor resources are directly related to the successful completion of a project. With the advanced technologies and innovations in the construction industry, it has become technically viable to implement automated tracking for construction materials. Through the development of an embedded sensor system, this paper illustrates the implementation of pilot experiments examining the accuracy of a system’s performance. A cost-benefit analysis is conducted to illustrate labor savings associated with construction materials handling by comparison between manual and sensor-based materials tracking. The presented embedded sensor system can be extended into diverse application areas in tracking and monitoring framework by providing improved method of field data acquisition and information management.     

Measuring nitric oxide in single neurons by capillary electrophoresis with laser-induced fluorescence: use of ascorbate oxidase in diaminofluorescein measurements

As a family of novel fluorescent indicators for nitric oxide (NO), the diaminofluoresceins (DAFs) have allowed real-time measurement of neuronal NO, an important gaseous neurotransmitter. However, the measurement of NO by the most commonly used NO sensor, 4,5-diaminofluorescein (DAF-2), is altered by two processes: the interaction of DAF-2 with intracellular dehydroascorbic acid (DHA) and the impact of ascorbic acid (AA) on the levels of N2O3, the intermediate product of the oxidation of NO that reacts with DAF-2. Similar AA/DHA effects are observed with other DAF probes, including DAF-FM and DAR-4M. To overcome these limitations, we use a specific enzymatic reaction to eliminate the confounding effect of AA on DAF quantitation of NO and then use capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection to distinguish the various reaction products. First, the enzyme ascorbate oxidase (AO) is used to catalyze the oxidation of AA to DHA. Next, CE-LIF separates the fluorescent products of the reaction of DAF-2 with NO and DHA. Control experiments, including standard mixtures and single neurons with added NO donor, successfully demonstrate the utility of this approach. This protocol is further tested with homogenates of the mouth area from the sea slug Aplysia californica, previously shown to be NO-positive, and individual nitric oxide synthase-containing buccal neurons from the freshwater snail, Lymnaea stagnalis. In each case, significant amounts of NO are detected. This AO DAF methodology is specific, effective, simple, and allows NO to be measured in single cells without detectable interference from other compounds.     

Simulation of Accuracy Performance for Wireless Sensor-Based Construction Asset Tracking

Abstract:   Today's mobile and remote construction applications, such as tracking of materials, equipment, and workers, demand high reliability and scalability of wireless sensor networks for a large-scale construction site. In particular, identifying the location of distributed mobile entities throughout wireless communications becomes the primary task to realize the remote tracking and monitoring of the construction assets. Even though several alternative solutions have been introduced by utilizing recent technologies, such as radio frequency identification (RFID) and the global positioning system (GPS), they could not provide a solid direction to accurate and scalable tracking frameworks in large-scale construction domains due to limited capability and inflexible networking architectures. This article introduces a new tracking architecture using wireless sensor modules and shows an accuracy performance using a numerical simulation approach based on the time-of-flight method. By combining radio frequency (RF) and ultrasound (US) signals, the simulation results showed an enhanced accuracy performance over the utilization of an RF signal only. The proposed approach can provide potential guidelines for further exploration of hardware/software design and for experimental analysis to implement the framework of tracking construction assets.     

Attribute-based evaluation of multiple continuous queries for filtering incoming tuples of a data stream

The filtering of incoming tuples of a data stream should be completed quickly and continuously, which requires strict time and space constraints. In order to guarantee these constraints, the selection predicates of continuous queries are grouped or indexed in most data stream management systems (DSMS). This paper proposes a new scheme called attribute selection construct (ASC). Given a set of continuous queries, an ASC divides the domain of an attribute of a data stream into a set of disjoint regions based on the selection predicates that are imposed on the attribute. Each region maintains the pre-computed matching results of the selection predicates. Consequently, an ASC can collectively evaluate all of its selection predicates at the same time. Furthermore, it can also monitor the overall evaluation statistics, such as its selectivity and tuple dropping ratio, dynamically. For those attributes that are employed to express the selection predicates of the queries, the processing order of their ASC’s can significantly influence the overall performance of a multiple query evaluation. The evaluation sequence can be optimized by periodically capturing the run-time tuple dropping ratio of its current evaluation sequence. The performance of the proposed method is analyzed by a series of experiments to identify its various characteristics.