• Journal of Internet Computing and Services
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• v.21 no.6
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• pp.81-94
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• 2020

This study developed evaluation indicators for the comfort experience of virtual reality (VR) headsets by classifying, defining, and weighting cybersickness-causing factors using the Delphi research method and analytic hierarchical process (AHP) approach. Four surveys were conducted with 20 experts on VR motion sickness. The expert surveys involved the 1) classification and definition of cybersickness-causing dimensions, classification of sub-factors for each dimension, and selection of evaluation indicators, 2) self-reassessment of the results of each step, 3) validity revaluation, and 4) final weighting calculation. Based on the surveys, the evaluation indicators for the comfort experience of VR headsets were classified into eight sub-factors: field of view (FoV)-device FoV, latency-device latency, framerate-device framerate, V-sync-device V-sync, rig-camera angle view, rig-no-parallax point, resolution-device resolution, and resolution-pixels per inch (PPI). A total of six dimensions and eight sub-factors were identified; sub-factor-based evaluation indicators were also developed.

• Asia pacific journal of information systems
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• v.32 no.2
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• pp.381-394
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• 2022

The present study aimed to examine the relationships between work-related support factors and attitude towards teleworking and explore the moderating effect of self-identity on that relationship. The present study collected data from 343 IT professionals in South Korea through a survey method and used hierarchical multiple regression analyses. In the results, first, the more supervisory or work-related supports participants perceive in teleworking platforms, the more favorable their attitudes towards teleworking. Second, the positive relationship between supervisory support and attitude towards teleworking is stronger for participants high rather than low in interdependent self-view. However, interdependent self-view was found to have no significance on the relationship between work colleague support and attitude towards teleworking. This study is the first to examine the integral model of work-related support factors of attitude towards teleworking and explore the moderating effect of self-identity in the teleworking process.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.1
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• pp.81-90
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• 2010

This paper presents H.264 coding schemes for multi-view video using the concept of layered depth image(LDI) representation and efficient compression technique for LDI. After converting those data to the proposed representation, we encode color, depth, and auxiliary data representing the hierarchical structure, respectively, Two kinds of preprocessing approaches are proposed for multiple color and depth components. In order to compress auxiliary data, we have employed a near lossless coding method. Finally, we have reconstructed the original viewpoints successfully from the decoded approach that is useful for dealing with multiple color and depth data simultaneously.

• The KIPS Transactions:PartA
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• v.9A no.4
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• pp.581-588
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• 2002

In implementing interactive multimedia systems, real-time visualization plays an important role. This paper presents efficient data structures and algorithms for real-time terrain navigation. Terrain data set is usually too huge to display as is. Therefore LOD (levels of detail) methods and view frustum culling are essential tools. This paper describes in detail compact hierarchical data structures, fast view frustum culling, and efficient LOD construction/rendering algorithms. Unlike previous works, we use a precise screen-space error metric for vertex removal and a strict error threshold allowing sub-pixel -sized errors only. Nevertheless, we can achieve 22 fps on average in a PC platform. The methods presented in this paper also satisfy almost all of the requirements for interactive real-time terrain Visualization.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.5
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• pp.1728-1743
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• 2021

Three-dimensional (3D) video scenes are complex and difficult to control, especially when scene switching occurs. In this paper, we propose two algorithms based on an incremental proportional-integral-derivative (PID) algorithm and a similarity analysis between views to improve the method of bit allocation for multi-view high efficiency video coding (MV-HEVC). Firstly, an incremental PID algorithm is introduced to control the buffer "liquid level" to reduce the negative impact on the target bit allocation of the view layer and frame layer owing to the fluctuation of the buffer "liquid level". Then, using the image similarity between views is used to establish, a bit allocation calculation model for the multi-view video main viewpoint and non-main viewpoint is established. Then, a bit allocation calculation method based on hierarchical B frames is proposed. Experimental simulation results verify that the algorithm ensures a smooth transition of image quality while increasing the coding efficiency, and the PSNR increases by 0.03 to 0.82dB while not significantly increasing the calculation complexity.

• Asia-Pacific Journal of Business
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• v.11 no.3
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• pp.21-46
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• 2020

Purpose - This study aims to find if the introduction of project finance perspective leads to any modification to the view of PM industry on CSFs of PPP and their relative importance rank. Design/methodology/approach - Through literature reviews, this study came up with a set of CSFs reflective of both perspectives. AHP method was applied for analysis by developing an Analytic Hierarchical Model from this set and survey questionnaires of pairwise comparison to solicit 46 qualified expert responses. Findings - This study concurs with PM industry to acknowledge 'risk allocation', 'legal framework' and 'quality of feasibility' as ones of most important CSFs. However, relative importance rank of individual CSFs goes through significant modification under this study in favor of 'sponsor commitment and quality' but against 'political environment', in particular. Research implications or Originality - Discussions on the CSFs led by PM industry have not been properly reflective of project finance perspective, which is injected into this study to cure the partiality. For researchers, findings of this study may call attention to financing perspective when they discuss CSFs of PPP. Practitioners may benefit from this study by allocating resources in view of this new finding when pursuing PPP projects.

• Journal of Internet Computing and Services
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• v.10 no.2
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• pp.99-116
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• 2009

For the mapping of two dimensional table structures of relational databases to the hierarchical XML documents, we apply the foreign key relationships of relational databases. In other words, the primary key of another table referenced by a foreign key of one tuple is mapped to the parent of the foreign key. Then XML hierarchies with order are expressed. In addition, the XML view file generated by the foreign key mappings shows side effects in the case of the relational database update for the satisfaction of referential integrity constraint in the foreign key. Thus, by inferring the foreign key roles at the generation of XML hierarchies, we can anticipate where the side effects occur in the hierarchies. We keep the XML view files up-to-date by reflecting the side effects to the XML files at the update of the underlying relational databases.

• Journal of the Korean Statistical Society
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• v.30 no.2
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• pp.179-192
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• 2001

When a statistical model has a hierarchical structure such as multilayer perceptrons in neural networks or Gaussian mixture density representation, the model includes distribution with unidentifiable parameters when the structure becomes redundant. Since the exact structure is unknown, we need to carry out statistical estimation or learning of parameters in such a model. From the geometrical point of view, distributions specified by unidentifiable parameters become a singular point in the parameter space. The problem has been remarked in many statistical models, and strange behaviors of the likelihood ratio statistics, when the null hypothesis is at a singular point, have been analyzed so far. The present paper studies asymptotic behaviors of the maximum likelihood estimator and the Bayesian predictive estimator, by using a simple cone model, and show that they are completely different from regular statistical models where the Cramer-Rao paradigm holds. At singularities, the Fisher information metric degenerates, implying that the cramer-Rao paradigm does no more hold, and that he classical model selection theory such as AIC and MDL cannot be applied. This paper is a first step to establish a new theory for analyzing the accuracy of estimation or learning at around singularities.

• Journal of Korean Elementary Science Education
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• v.34 no.1
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• pp.142-152
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• 2015

The purpose of this study was to identify the differences in eye movement pattern shown in shown in classification process between the scientifically gifted and general students in elementary schools. The subjects for the research consisted of 16 gifted students in special education center for the gifted at Seoul National University of Education and 22 general students at G elementary schools. The tasks consisted of four hierarchical biology classification tasks and one non-hierarchical tasks. SMI's Eye Tracker (iView $X^{TM}$ RED) was used to collect eye movement data while the Begaze software analyzed the task performing process and eye movements. The findings of this study were twofold. First, there was a significant difference in students' fixation duration by students' academic achievement level. Gifted students spent little time on scanning details and found the features successfully. Second, the process of the classification is different by students' academic achievement. General students spent more time to gaze the salient features not relevant features. They had a difficulty to find the element to classify.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2004.11a
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• pp.39-49
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• 2004

When there is a lack of detailed kinetic information, dFBA(dynamic flux balance analysis) has correctly predicted cellular behavior under given environmental conditions with FBA and different ial equations. However, until now, dFBA has centered on substrate concentration, cell growth, and gene on/off, but a detailed hierarchical structure of a regulatory network has not been taken into account. For this reason, the dFBA has limited the represen tation of interactions between specific regulatory proteins and genes and the whole transcriptional regulation mechanism with environmental change. Moreover, to calculate optimal metabolic flux distribution which maximizes the growth flux and predict the b ehavior of cell system, linear programming package(LINDO) and spreadsheet package(EXCEL) have been used simultaneously. thses two software package have limited in the visual representation of simulation results and it can be difficult for a user to look at the effects of changing inputs to the models. Here, we descirbes the construction of hierarchical regulatory network with defined symbolsand the development of an integrated system that can predict the total control mechanism of regulatory elements (opero ns, genes, effectors, etc.), substrate concentration, growth rate, and optimal flux distribution with time. All programming procedures were accoplished in a visual programming environment (LabVIEW).