• Journal of the Korea Concrete Institute
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• v.26 no.4
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• pp.507-515
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• 2014

Although the construction joints of a concrete structure are properly treated with some measures, leakage has frequently occurred. A series of tests on the bond characteristics between new and old concrete were carried out in this study, assuming that the leakage at the construction joints has certain relationship with the bond of concrete. To assess the bond characteristics under various conditions, a number of specimens were made that have an interface between new and old concrete and bond strength, flexural strength and splitting tensile strength were measured. Main test variables are type and amount of mineral admixtures, treatment method of the interface and type of waterstops. In addition, the effects of placing interval between the concrete and of the age of the strength tests were investigated. The test results showed a slightly increased bond strength when applying mineral admixtures, which can be attributed to the interface filled with the calcium silicate hydrate that is formed by pozzolanic reaction. On the other hand, the bond strength was higher when the interface was treated rough and dry, and the roughness of a waterstop affected the bond capacity of the waterstop. Also, an assessment is required that considers the type of strength test because the bond strength varied according to the test methods.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.420-420
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• 2013

We investigated oxygen plasma effect on defect states near the interface of AlGaN/GaN High Electron Mobility Transistor (HEMT) structure grown on a silicon substrate. After the plasma treatment, electrical properties were evaluated using a frequency dependant Capacitance-Voltage (C-V) and a temperature dependant C-V measurements, and a deep level transient spectroscopy (DLTS) method to study the change of defect densities. In the depth profile resulted from the temperature dependant C-V, a sudden decrease in the carrier concentration for two-dimensional electron gas (2DEG) nearby 250 K was observed. In C-V measurement, the interface states were improved in case of the oxygen-plasma treated samples, whereas the interface was degraded in case of the nitrogen-plasma treated sample. In the DLTS measurement, it was observed the two kinds of defects well known in AlGaN/GaN structure grown on sapphire substrate, which have the activation energies of 0.15 eV, 0.25 eV below the conduction band. We speculate that this defect state in AlGaN/GaN on the silicon substrate is caused from the decrease in 2DEG's carrier concentrations. We compared the various DLTS signals with filling pulse times to identify the characteristics of the newly found defect. In the filling pulse time range under the 80 us, the activation energies changed as the potential barrier model. On the other hand, in the filling pulse time range above the 80 us, the activation energies changed as the extended potential model. Therefore, we suggest that the found defect in the AlGaN/GaN/Si structure could be the extended defect related with AlGa/N/GaN interface states.

• Smart Media Journal
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• v.1 no.2
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• pp.40-46
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• 2012

In this paper, we describe interactive contents which is used the result of the inputted interface recognizing vision-based body gesture. Because the content uses the imp which is the common culture as the subject in Asia, we can enjoy it with culture familiarity. And also since the player can use their own gesture to fight with the imp in the game, they are naturally absorbed in the game. And the users can choose the multiple endings of the contents in the end of the scenario. In the part of the gesture recognition, KINECT is used to obtain the three-dimensional coordinates of each joint of the limb to capture the static pose of the actions. The vision-based 3D human pose recognition technology is used to method for convey human gesture in HCI(Human-Computer Interaction). 2D pose model based recognition method recognizes simple 2D human pose in particular environment On the other hand, 3D pose model which describes 3D human body skeletal structure can recognize more complex 3D pose than 2D pose model in because it can use joint angle and shape information of body part Because gestures can be presented through sequential static poses, we recognize the gestures which are configured poses by using HMM In this paper, we describe the interactive content which is used as input interface by using gesture recognition result. So, we can control the contents using only user's gestures naturally. And we intended to improve the immersion and the interest by using the imp who is used real-time interaction with user.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.1
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• pp.25-32
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• 2016

The purpose of this study is to evaluate the performance on the compressive bonding shear strength of ultra-high strength steel fiber reinforced cementitous composites(UHSCC). As a result of compressive bonding shear strength through Direct shear test, It was found that the specimen($150{\times}150{\times}150mm$) of NC(Normal concrete) + NC showed similar compressive bonding shear strength at whole experimental level. On the other hand, the specimen of UHSCC + UHSCC showed decrease of compressive bonding shear strength from after 30 minutes of the retarded placement than 0 minute. As a result of analyzing failure mode of bonding interface, It was found that the specimen of NC + NC showed mixed failure at whole experimental level. In case of the specimen of UHSCC + UHSCC, it showed interface failure from the specimen that are 30 minutes, 60 minutes and 90 minutes of delay of concrete placing. As a result of analyzing XRD test in terms of the placement interface on the specimen of NC and UHSCC, relatively much amount of $SiO_2$ was detected from the specimen of UHSCC than that of NC. It is judged that the most of main components of coating film shown in the specimen of UHSCC is $SiO_2$. In conclusion, it is judged that UHSCC which is made from after 30 minutes of delay of concrete placing is unable to be used as structural member because of deterioration of bonding performance. From later study, it is judged that the improvement of bonding performance from the part of cold joint occurrence is necessary through the interface preparation method.

• Korean Journal of Materials Research
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• v.10 no.10
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• pp.684-690
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• 2000

In order to study effects of interfacial layers between $Pb(Zr,Til)Q_3(PZT)$ films and electrodes for Metal-Ferroelectric-MetaI(MFM) structure capacitors, we have fabricated the capacitors with the Pt/PZT/interfacial-layer/Pt/$TiO_2/SiO_2$/Si structure. $PbTiO_3(PT)$ interfacial layers were formed by sol-gel deposition and PbO, ZrO, and $TiO_2$ thin layers were deposited by reactive sputtering. $TiO_2$ interface layers result in the finest grains of PZT(crystalline Temp. $600^{\circ}C$) films compare to $PbO_2\;and\;ZrO_2$ layers. However, as the thickness of $TiO_2$ layer increases. PZT thin films become rough and electrical characteristics were deteriorated due to remained anatase phase. On the other hand. PT interface layers result in improved morphology of PZT films and do not significantly change ferroelectric properties. It is a also observed that seed layers at the middle and top of PZT films do not give significant effects on grain size but the PT seed layer at the interface between the bottom electrode and the PZT films results in the small grain size.

• Journal of the Korea Society of Computer and Information
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• v.15 no.9
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• pp.77-85
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• 2010

As various convergency products have been actively developed, the study on user interface has been conducted a lot, and for more specific direction, users' experience-oriented user interface from user-oriented studies is recently developed. Such a tendency aiming to focus on product development to express users' emotion, the next step in the user-oriented development had difficulties in an objective approach, so the data based on previous users' experiences were presented as the basic data to establish user interface design process with grounds and design direction, and therefore it is available to show more specific and objective grounds. From this perspective, such psychological variables showing users' experiences like age and job are studied through surveys of users at the development of products, and products according to the variables are released. On the other hand, the products considering psychological difference distinguishing users' experiences as the cultural cap are not progressed yet. Despite the understanding of cultural difference, its decisive grounds are hard to distinguish like age, and job. Therefore, the cognitive concept about how to design menu information structure according to accident types that can be considered regarding user interface design among theoretical backgrounds about cultural difference. As the category according to the range of things among accident types, it is divided into analytical type and relational type to conduct a test on similarity and relations about the representative digital TV's menu information of the convergency product. As the result, analytical type and relational type showed difference and this study aims to use menu information concept considering this difference as explanatory variables of the users' experience-oriented development.

• Journal of KIISE:Software and Applications
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• v.29 no.11
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• pp.837-850
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• 2002

In this paper, we propose an EEG-based response time prediction method during a yes/no cognitive decision task. In the experimental task, a subject goes through responding of visual stimulus, understanding the given problem, controlling hand motions, and hitting a key. Considering the subject's varying brain activities, we model subjects' mental states with defining CT (cut time), ST (selection time), and RP (repeated period). Based on the assumption between ST and RT in the mental model, we predict subjects' response time by detection of selection time. To recognize the subjects' selection time ST, we extract 3 types of feature from the filtered brain waves at frequency bands of $\alpha$, $\beta$, ${\gamma}$ waves in 4 electrode pairs combined by spatial relationships. From the extracted features, we construct specific rules for each subject and meta rules including common factors in all subjects. Applying the ST detection rules to 8 subjects gives 83% success rates and also shows that the subjects will hit a key in 0.73 seconds after ST detected. To validate the detection rules and parameters, we test the rules for 2 subjects among 8 and discuss about the experimental results. We expect that the proposed detection method can be a basic technology for brain-computer-interface by combining with left/right hand movement or yes/no discrimination methods.

• Journal of Korea Game Society
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• v.6 no.2
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• pp.3-12
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• 2006

Recently, Many 3D augmented reality games that provide strengthened immersive have appeared in the 3D game environment. In this article, we describe a barehanded interaction method based on human hand gestures for augmented reality games. First, feature points are extracted from input video streams. Point features are tracked and motion of moving objects are computed. The shape of the motion trajectories are used to determine whether the motion is intended gestures. A long smooth trajectory toward one of virtual objects or menus is classified as an intended gesture and the corresponding action is invoked. To prove the validity of the proposed method, we implemented two simple augmented reality applications: a gesture-based music player and a virtual basketball game. In the music player, several menu icons are displayed on the top of the screen and an user can activate a menu by hand gestures. In the virtual basketball game, a virtual ball is bouncing in a virtual cube space and the real video stream is shown in the background. An user can hit the virtual ball with his hand gestures. From the experiments for three untrained users, it is shown that the accuracy of menu activation according to the intended gestures is 94% for normal speed gestures and 84% for fast and abrupt gestures.

• Journal of Korean Institute of Industrial Engineers
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• v.38 no.3
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• pp.182-190
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• 2012

With the progress of both wire and wireless home networking technology, various projects on smart home have been carried out in the world (Harper, 2003), and at the same time, new approaches to interact with smart home systems efficiently and effectively have also been investigated. A gesture-based interface is one of these approaches. Especially with advance of gesture recognition technologies, a variety of research studies on gesture interactions with the functions of IT devices have been conducted. However, there are few research studies which suggested and investigated the use of gestures for controlling smart home appliances. In this research the gestures for selected smart home appliances are suggested based on a user centered approach. A total of thirty-eight functions were selected, and a total of thirty participants generated gestures for each function. Based on the Nielsen (2004), Lee et al. (2010) and Kuhnel et al. (2011), the gesture with the highest frequency for each function (Top gesture) has been suggested and investigated.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.6
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• pp.469-476
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• 2012

In this paper, a finite element domain decomposition method using local and mixed Lagrange multipliers for a large scal structural analysis is presented. The proposed algorithms use local and mixed Lagrange multipliers to improve computational efficiency. In the original FETI method, classical Lagrange multiplier technique was used. In the dual-primal FETI method, the interface nodes are used at the corner nodes of each sub-domain. On the other hand, the proposed FETI-local analysis adopts localized Lagrange multipliers and the proposed FETI-mixed analysis uses both global and local Lagrange multipliers. The numerical analysis results by the proposed algorithms are compared with those obtained by dual-primal FETI method.