• Korean Journal of Construction Engineering and Management
• /
• v.25 no.2
• /
• pp.69-80
• /
• 2024

Currently rebar spacing inspection is carried out by human inspectors who heavily rely on their individual experience, lacking a guarantee of objectivity and accuracy in the inspection process. In addition, if incorrectly placed rebars are identified, the inspector need to correct them. Recently, laser scanning and AR technologies have been widely used because of their merits of measurement accuracy and visualization. This study proposes a technology for rebar spacing inspection and fixing by combining laser scanning and AR technology. First, scan data acquisition of rebar layers is performed and the raw scan data is processed. Second, AR-based visualization and fixing are performed by comparing the design model with the model generated from the scan data. To verify the developed technique, performance comparison test is conducted by comparing with existing drawing-based method in terms of inspection time, error detection rate, cognitive load, and situational awareness ability. It is found from the result of the experiment that the AR-based rebar inspection and fixing technology is faster than the drawing-based method, but there was no significant difference between the two groups in error identification rate, cognitive load, and situational awareness ability. Based on the experimental results, the proposed AR-based rebar spacing inspection and fixing technology is expected to be highly useful throughout the construction industry.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2006.11a
• /
• pp.136-139
• /
• 2006

In this paper we propose a small form factor actuator using an inclined motion guide for auto-focusing and zoom motions for mobile information devices. The novel structure using the inclined motion guide and a lens-supporting beam converts the circular motion by an ultrasonic motor into the linear motion of the optical lens. The proposed actuator has a simple structure to minimizing the mechanical tolerance, and the stroke is easy to modify by controlling the inclined angle. Experiments using a prototype verify the validity of the model as small form factor optical actuator.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.1017-1020
• /
• 2004

It is not efficient and scarcely out of the question to use commercial expensive electron beam lithography system widely used for semiconductor fabrication process for the manufacturing application field of various devices in the small business scope. Then scanning electron microscope based electron beam machining system is maybe regarded as a powerful model can be used for it simply. To get a complete suite of thus proper system, column unit build up with several electo-magnetic lens is necessarily required more than anything else to modify scanning electron microscope. In this study, various components included several electro-magnetic lens and main body which are essentially constructed for column unit are designed and manufactured. And this established column unit will be used for next connected study in the development step of scanning electron microscope based electron beam machining system.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 2000.04a
• /
• pp.301-305
• /
• 2000

The present study is part of the Special Research Project for the Construction of a Kansei Sensory Evaluation Model that is currently underway at the University of Tsukuba. In this study, a robot was operated by remote control at an actual art museum as part of a preliminary experiment. The results obtained therefrom were used to consider how people might view exhibits. In a previous study, a standard lens and s wide-angle lens were used to analyze differences in sensory-based movements, while VRML was used to analyze differences in these movements between a virtual and an actual museum. In the present study, the time delay in remote operation, which is currently unavoidable, placed some restrictions on the degree of freedom with which exhibits could be viewed, but it was apparent that sensory evaluation could be possible depending on the search behavior and viewing time. Furthermore specific viewing behaviors using the robot were observed, suggesting that new Kansei sensory perceptions were derived from these behaviors.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.5
• /
• pp.890-896
• /
• 2010

Increasing styling features for automotive headlamps speed up the focus of understanding condensation at inner surfaces. Water vapor condensation on the inside surface of the headlamp lens is an essential factor that affects secure front view and headlamp life. One of the headlamps of automobile which is one of the most popular in Korea was chosen for the present analysis. In the basis of the experimental data of automobile given by a manufacturer, boundary conditions were defined and free convection of the air inside the headlamp and radiation from the bulb to the other surfaces are considered. As a result, temperature distribution of the inside surface of the headlamp lens are approximately the same as the experimental result.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11a
• /
• pp.397.2-397
• /
• 2002

There are 4 servo systems in a DVD drive such as a focus servo system, a tracking servo system, a sled servo system and a spindle servo system. Focus servo system maintains relative distance between lens and disk. In this paper, two plant models for the focus servo system will be presented. One of them is newly developed and the other is conventional. Focus error signal between lens and disk is detected using LDV 2 beam method. (omitted)

• 한국가시화정보학회:학술대회논문집
• /
• 2001.12a
• /
• pp.123-137
• /
• 2001

PIV (particle image velocimetry) systems use a camera to take snapshots of particles carried by a fluid at some precise instants. Signal processing methods are then used to compute the flow velocity field. In this paper, the design of the camera objective (optics) is addressed. The optimization is done in order to maximize the signal-to-noise ratio of in-focus particles. Four different kinds of noise are considered: photon shot noise, thermal and read noise, background glow shot noise, and noise made by the other particles. A semi-empirical model for the lens aberrations of a two-doublet objective is first addressed, since further, it is shown that lens aberrations (low f-value $f_{\#}$) should be used instead of the Fraunhofer diffraction (high f-value) for the fitting of the particle image size with the pixel size. Other important conclusions of the paper include the expression of optimum values for the magnification M, for the exposure period $\tau$ and for the pixel size $\xi$.

• The Bulletin of The Korean Astronomical Society
• /
• v.43 no.1
• /
• pp.62.2-62.2
• /
• 2018

From the gaussian, near scale-invariant density perturbations observed in the CMB to the late time clustering of galaxies, CDM provides a minimal theoretical explanation for a variety of cosmological data. However accepting this explanation, requires that we include within our cosmic ontology a vacuum energy that is ~122 orders of magnitude lower than QM predictions, or alternatively a new scalar field (dark energy) that has negative pressure. Alternatively, modifications to Einstein's General Relativity have been proposed as a model for cosmic acceleration. Recently there have been many works attempting to test for modified gravity using the large scale clustering of galaxies, ISW, cluster abundance, RSD, 21cm observations, and weak lensing. In this work, we compare various modified gravity models using cosmic shear data from the Deep Lens Survey as well as data from CMB, SNe Ia, and BAO. We use the Bayesian Evidence to quantify the comparison robustly, which naturally penalizes complex models with weak data support. In this poster we present our methodology and preliminary constraints on f(R) gravity.

• The Journal of Information Systems
• /
• v.23 no.3
• /
• pp.143-164
• /
• 2014

This study draws on status quo bias theoretic perspective as a meta-theoretic lens to explain why individuals have resists to adopt smart devices for their tasks. More specifically, we attempted to examine the relationships among user's resist, perceived usefulness and individual productivity in the smart work context. By employing the status quo bias theoretic perspective, we develop and test our research model by using a survey data from 235 individual users. We demonstrate that satisfaction on the current state influence users' resist, and also the users' resist is mediated by perceived usefulness on individual productivity. From the status quo bias view, this study presents an alternative meta-theoretical lens in order to understand individuals' resist in the smartwork context.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.11a
• /
• pp.226-233
• /
• 2003

There are many researches going on to develop the information storage devices using Blue-ray disc and DVD as a demand for high-density information storage devices is highly increasing. This high-density information storage device requires a short-wave laser and objective lens of high numerical aperture set in fer its operation. And, that brings out rapid decrease of tilt tolerance. Therefore, it is necessary that an actuator should control tilt motions to get a stable signal. In this paper, a new mathematical form of 3-D.O.F coupled model is formulated and magnetic circuit in constraints is most effectively designed with the use of the moving coil type actuator in higher sensitivity. Further, this paper presents a tilt coil whose rotational center point is put on that of the lens through the variation of tilt coil and proposes a 3-axis actuator with high sensitivity improved in its dynamic property through its structure analysis.