"Internet Gaming Disorder" in China: Biomedical Sickness or Sociological Badness?

Trent M. Bax SAGE 2015 SAGE Open Vol.10 No.1

Seeing Something New: Effects of Elaboration and Repetition on the Pattern of Explicit and Implicit Attitude Formation

김도영 SAGE 2013 SAGE Open Vol.3 No.3

Contextual synchronization for efficient social collaborations in enterprise computing: A case study on TweetPulse

SAGE Publications 2013 Concurrent engineering Vol.21 No.3

<P>It is important to be aware of user contexts for supporting efficient collaborations among them. The goal of this article is to present a social collaboration platform where we can understand (1) how the user contexts are dynamically changing over time and (2) how the user contexts are mixed with multiple sub-contexts together. Therefore, we have implemented TweetPulse, which is a Twitter-based tool for context monitoring and propagation system in a given social network. TweetPulse can match contexts of the users (and integrate them) to find the most relevant users. Eventually, collaborations among users are <I>contextually synchronized</I> by dynamically organizing a number of communities. A set of users in each community can share their skills and core competencies with each other. We have shown the experimental results collected from a collaborative information searching system in terms of (1) setting thresholds, (2) searching performance, and (3) robustness testing.</P>

Two-Stage Hidden Markov Model in Gesture Recognition for Human Robot Interaction

Nguyen-Duc-Thanh, Nhan,Lee, Sungyoung,Kim, Donghan SAGE Publications 2012 International Journal of Advanced Robotic Systems Vol.9 No.2

Experimental studies on the aerodynamic characteristics of a pantograph suitable for a high-speed train

Lee, Yeongbin,Rho, Joohyun,Kim, Kyu Hong,Lee, Dong Ho,Kwon, Hyeok Bin SAGE Publications 2015 Proceedings of the Institution of Mechanical Engin Vol.229 No.2

<P>The aerodynamic properties of a pantograph that is under consideration for application on Korean high-speed trains are experimentally investigated. The selected experimental models were one-quarter scale pantographs (a double-arm pantograph, single-arm pantograph and a periscope pantograph) with either a rectangular panhead or a panhead with an optimized streamlined shape. To increase the performance and the robustness of the pantograph, the drag coefficient and the fluctuation of the lift coefficient along the angle of attack are simultaneously minimized. In order to confirm the aerodynamic enhancement of the pantograph due to the optimized panhead, the aerodynamic forces are compared with those of a pantograph with a rectangular panhead. To investigate the aerodynamic force distribution of a pantograph, the aerodynamic forces of the lift and drag of the pantograph are measured in wind tunnel tests and analyzed in terms of the pantograph’s components. In addition, wake flows are examined based on variations of the shape of the panhead.</P>

Nonlinear aircraft tracking filter utilizing a point mass flight dynamics model

Jeon, Daekeun,Eun, Yeonju,Bang, Hyochoong,Yeom, Chanhong SAGE Publications 2013 Proceedings of the Institution of Mechanical Engin Vol.227 No.11

<P>A nonlinear aircraft tracking filter using a point mass flight dynamics model with three degrees of freedom is presented. While the models used by conventional air traffic control tracking filters are based on simple kinematics, the model for the present filter is based not only on kinematic relations but also on three-dimensional aircraft translational force equations and control variables. This allows for practical and sophisticated implementation of the attitude effects on translational acceleration. The control variables, which consist of the angle of attack, roll angle, and thrust setting, are treated as states with random processes. Tracking with simulation data indicates that the present filter is superior to other single and multiple model-based filters in terms of position and course accuracy, and the model associated with it is insensitive to flight motion types and design parameters. The results of tracking with real flight data also correspond well with those found by tracking with the simulation data.</P>

Multi-model approaches to three-axis missile autopilot design under aerodynamic roll angle uncertainty

Won, D-Y,Tahk, M-J,Kim, Y-H,Kim, H J SAGE Publications 2012 Proceedings of the Institution of Mechanical Engin Vol.226 No.9

<P>The problem of designing a robust three-axis missile autopilot that operates under aerodynamic roll angle uncertainty is addressed in this article. A finite number of local state-space models over an aerodynamic roll angle envelope are developed as a multi-model to represent uncertainty bounds. Two design methods with multi-objective output-feedback control are proposed. In the first approach, a classical three-loop autopilot structure is slightly modified for the multivariable autopilot design. The optimal gains in the autopilot structure are automatically obtained by using a co-evolutionary optimization method that addresses competing specifications and constraints. In the second approach, the mixed H-2/H-infinity performance criteria are guaranteed by multi-objective control synthesis via optimization techniques. Both design approaches are used in non-linear simulations with variations in the aerodynamic roll angle to provide satisfactory performance as a three-axis missile autopilot.</P>

Ethnic Giving Versus Mainstream Giving by Foreign-Born Korean Immigrants in California

Moon, Seong-gin,Choi, Sang Ok SAGE Publications 2013 Nonprofit and voluntary sector quarterly Vol.42 No.4

<P>Based on a large-scale philanthropic survey conducted in California, this paper empirically examines the determinants of <I>ethnic giving</I> versus <I>mainstream giving</I> practices and the interactive relationships between the two observed among foreign-born Korean immigrants. The results of our bivariate probit regression analysis suggest several interesting findings. First, acculturation serves significant functions in immigrants’ decisions to give to mainstream organizations, but does not appear to affect ethnic giving decisions as profoundly. Second, U.S. educational experiences and gender are strong predictors of mainstream giving practices, whereas household incomes and religiosity figure significantly in terms of explaining ethnic giving practices. Additionally, citizenship is related weakly to ethnic giving practices. Finally, two distinctive giving practices are negatively interrelated, meaning that immigrants who donate to ethnic organizations are less likely to give to mainstream organizations, and vice versa.</P>

Efficient global optimization for S-duct diffuser shape design

Bae, HyoGil,Park, SooHyung,Kwon, JangHyuk SAGE Publications 2013 Proceedings of the Institution of Mechanical Engin Vol.227 No.9

<P>The efficient global optimization method is a global optimization technique based on the stochastic kriging model to efficiently search the global optimum in a design space. Efficient global optimization selects the next sample point in the view of the probability that a global minimum is located. To present the probability, the efficient global optimization method introduces the expected improvement function. The mean and variance at the untried point provided from the kriging model are used to calculate the expected improvement function. Efficient global optimization selects the maximum expected improvement point as the next sample point. After validating the efficient global optimization method by several test functions, we applied it to a diffusing S-duct shape design problem which needs a computationally expensive turbulent computational fluid dynamics analysis. The design objective is to improve the total pressure recovery of the S-duct. The improved S-duct shape was searched globally through the efficient global optimization method. Our results confirmed that the efficient global optimization method can efficiently provide a meaningful engineering result in the S-duct shape design.</P>

Reputation-based cluster head elections in wireless sensor networks

Wang, Gicheol,Cho, Gihwan SAGE Publications 2013 Simulation Vol.89 No.7

<P>In clustered sensor networks, because CHs (cluster heads) collect data from sensors and transmit the aggregated data to the sink, it is very important to elect the CHs in a secure manner. In order to protect CH elections from attackers, unpredictability, non-manipulability, and agreement property should be guaranteed in CH elections. However, existing schemes for secure CH election cannot prevent intelligent attackers from violating the properties via cooperation. In this paper, we propose a scheme that securely elects CHs by detecting intelligent attackers and excluding them. For every CH election round, each CH candidate provides reputation values to other CH candidates according to their behavior and extracts real reputation values. Then, each node evaluates the real reputation values of members in its cluster and excludes some disreputable nodes from CH candidates. The scheme greatly enhances the non-manipulability and agreement property of CH election results compared to other rival schemes. Furthermore, the scheme presents higher non-manipulability and higher agreement property than other schemes, even in an environment where message losses can occur.</P>