• Asia pacific journal of information systems
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• 제26권1호
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• pp.41-65
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• 2016

What prevails in the today's research on social media is a functional view of technology. Technology is regarded as a set of technical devices used to conduct specific social functions, such as personal communication, social networking, public posting, and corporate advertising, among others. This paper proposes that such a functional view of technology renders social media research unduly limited and constrained in its scope, level, and direction of inquiry. Problematizing on some representative social media research efforts in the field of IS, this paper provides an alternative perspective, that is, to view social media as a technology-for-being that exerts a deeper level of influence on our existence, molding and shaping the nature and mode of being itself. Such a technology-for-being perspective has been rarely explored or subscribed to in the present IS social media research. Building upon the new conception of social media as a technology-for-being, this essay explores the quality of being in the context of social media. Five such qualities are discussed, including virtuality, materiality, externality, liquidity, and hybridity. The essay also explores the deep structural problems of research to guide future social media research. Six of such problems include Problematize-the-Natural, Follow-the-Actor, Welcome-the-Frankenstein, Weber-meets-Frankenstein, Freud-meets-Frankenstein, and Marx-meets-Frankenstein. The essay concludes with discussions on the implications of the essay, its limitations, and suggestions for future work.

• 한국결정성장학회지
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• 제9권4호
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• pp.387-395
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• 1999

The strain, surface and interfacial energies of III-V ternary systems were calculated for three kinds of structure modes: the Frank-van der Merwe(FM) mode, the Stanski-Krastanov(SK) mode and the Volmer-Weber(VW) mode. The free energy for each mode was estimated as functions of thickness and composition or lattice misfit. Through comparison of the free energy of each mode, it was found that the thickness-composition phase diagrams of III-V ternary systems can be determined only by considering the balance of the free energy and three kinds of structure modes appear in the phase diagrams. The SK mode appears only when the lattice misfit is large and/or the lattice layer is thick. The most stable structure of the SK mode is a cluster with four lattice layers or minimum thickness on a wetting layer of increasing lattice layers. The VW mode appears when the lattice misfit is large and the lattice layer is thin and only in the INPSb/InP and GaPSb/GaP system which have the largest lattice misfit of III-V ternary systems. The stable region of the SK mode in the GaPSb/GaP and InPSb/InP phase diagrams is largest of all because the composition dependence of the strain energy of these systems is stronger than that of the other systems. The critical number of lattice layers below which two-dimensional(2D) layers precede the three-dimensional(3D) nucleation in the SK mode at x=1.0 depends on the lattice misfit.

• Safety and Health at Work
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• 제14권3호
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• pp.303-308
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• 2023

Background: Occupational workers at altitudes are more prone to falls, leading to catastrophic outcomes. Acrophobia, height-related anxiety, and affected executive functions lead to postural instabilities, causing falls. This study investigated the effects of repeated virtual height exposure and training on cognitive processing and height-related anxiety. Methods: Twenty-eight healthy volunteers (age 20.48 ± 1.26 years; mass 69.52 ± 13.78 kg) were recruited and tested in seven virtual environments (VE) [ground (G), 2-story altitude (A1), 2-story edge (E1), 4-story altitude (A2), 4-story edge (E2), 6-story altitude (A3), and 6-story edge (E3)] over three days. At each VE, participants identified occupational hazards present in the VE and completed an Attitude Towards Heights Questionnaire (ATHQ) and a modified State-Trait Anxiety Inventory Questionnaire (mSTAIQ). The number of hazards identified and the ATHQ and mSTAIQ scores were analyzed using a 7 (VE; G, A1, A2, A3, E1, E2, E3) x 3 (DAY; DAY 1, DAY 2, DAY 3) factorial repeated measures analysis of variance. Results: The participants identified the lowest number of hazards at A3 and E3 VEs and on DAY 1 compared to other VEs and DAYs. ATHQ scores were lowest at G, A1, and E1 VEs. Conclusion: Cognitive processing is negatively affected by virtual altitudes, while it improves with short-term training. The features of virtual reality, such as higher involvement, engagement, and reliability, make it a better training tool to be considered in ergonomic settings. The findings of this study will provide insights into cognitive dual-tasking at altitude and its challenges, which will aid in minimizing occupational falls.

• Korean Chemical Engineering Research
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• 제47권6호
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• pp.720-726
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• 2009

가압으로 운전되는 삼상슬러리 기포탑에서 기포 체류량과 압력강하를 목적함수로하여 기포탑의 설계 및 scale-up을 위한 수력학적 similarity를 고찰하였다. 또한, 본 연구에서 선택한 각 실험변수가 기포탑의 직경변화에 따라 기포탑 내 기포 체류량에 미치는 영향을 분석하였다. 슬러리 기포탑에서 기체체류량 및 압력강하의 결정에 영향을 미치는 주요 인자로써 기체유속($U_G$), 연속 슬러리 상의 점도(${\mu}_{SL,eff}$) 및 표면장력(${\rho}_{SL}$), 운전압력의 변화에 따라 변화하는 기체상의 밀도(${\rho}_G$)와 슬러리 밀도(${\rho}_{SL}$)의 차($\rho_{SL}$-${\rho}_G$), 기포탑 내부에서 단위길이 당 압력강하(${\Delta}P/L$), 기포탑의 직경(D) 그리고 기포탑에서 다상흐름에 작용하는 중력의 영향을 고려하기 위해 중력가속도(g) 등을 선정하였다. 선정된 7개의 슬러리 기포탑의 수력학적 특성에 영향을 미치는 파라메타들과 3개의 기본차원들로부터 차원해석에 의해 수력학적 특성을 지배하는 4개의 무차원 군을 도출하였다. 도출된 무차원 군인 레이놀즈 수, 프라우드 수 그리고 웨버 수 등이 기포탑에서 기포체류량에 미치는 영향을 검토하였다. 기포탑 내부에서의 압력강하와 기체 체류량 등을 무차원 군의 상관식으로부터 효과적으로 예측할 수 있었다. 본 연구의 결과는 가압슬러리 기포탑의 설계 및 scale-up 등에 매우 유용한 정보를 제공할 수 있을 것으로 사료된다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권1호
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• pp.16-23
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• 2005

It is commonly acknowledged that bone morphogenic protein (BMP-2) functions as a potential osteogenic inducer in bone formation. Recently, several papers reported that bone marrow-derived stem cell (BMSC) from human is not responsive to BMP-2 in comparison to high capacity of BMP-2 in the osteoinduction of stromal cell derived from bone marrow of rodent animals such as rat or mouse. In this study, we characterized BMSC derived from 11 years old donor for the responsiveness to rhBMP-2, dexamethasone (Dex) and 1,25-dihydroxyvitamin D (vitamin D), in order to analyze their function in the early osteogenesis. The effect of over mentioned agents was evaluated by means of assessing alkaline phosphatase (ALP) activity/staining, RT-PCR analysis and von Kossa staining. In addition, we analyzed the meaning of expressed several osteoblastic markers such as alkaline phosphatase, collagen typeI, osteopontin, bone sialoprotein and osteocalcin with relation to either differentiation or mineralization. Only in the presence of Dex, human BMSC could commit osteoblastic differentiation and matrix mineralization, and either BMP-2 or vitamin D treatment was not able to induce. But BMP-2 or Vitamin D showed potential synergy effect with Dex. ALP and bone sialoprotein were clearly expressed in response of Dex treatment compared to weak expression of osteopontin in early osteogenesis. Therefore, we expect that this study will contribute partly to elucidiating early osteogenesis mechanism in human, but variations among bone marrow donors must be considered through further study.