• Journal of Power Electronics
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• v.17 no.1
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• pp.253-261
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• 2017

For a single-phase active power filter (APF), designing a more efficient algorithm to guarantee accurate and fast harmonics extraction with a lower computing cost is still a meaningful topic. The common idea still employs a IRPT-based Park transform, which was originally designed for 3-phase applications. Therefore, an additional virtual signal generation (VSG) link is necessary when it is used in the single-phase condition. This method, with virtual signal generation and transform, is obviously not the most efficient one. Regarding this problem, this paper proposes a novel harmonics extraction algorithm to further improve efficiency. The new algorithm is based on the principle of trigonometric orthogonal functions (TOF), and its mathematical principle and physical meaning are introduced in detail. Its implementation and superiority in terms of computation efficiency are analyzed by comparing it with conventional methods. Finally, its effectiveness is well validated through detailed simulations and laboratory experiments.

• Journal of the Korean Society for information Management
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• v.25 no.4
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• pp.131-148
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• 2008

The purposes of the study are to design a key-frame extraction algorithm for constructing the virtual storyboard surrogates and to evaluate the efficiency of the proposed algorithm. To do this, first, the theoretical framework was built by conducting two tasks. One is to investigate the previous studies on relevance and image recognition and classification. Second is to conduct an experiment in order to identify their frames recognition pattern of 20 participants. As a result, the key-frame extraction algorithm was constructed. Then the efficiency of proposed algorithm(hybrid method) was evaluated by conducting an experiment using 42 participants. In the experiment, the proposed algorithm was compared to the random method where key-frames were extracted simply at an interval of few seconds(or minutes) in terms of accuracy in summarizing or indexing a video. Finally, ways to utilize the proposed algorithm in digital libraries and Internet environment were suggested.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.2
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• pp.94-100
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• 2016

A virtual power plant (VPP) technology is a cluster of distributed generation installations. VPP system is that integrates several types of distributed generation sources, so as to give a reliable overall power supply. Virtual power plant systems play a key role in the smart grids concept and the move towards alternative sources of energy. They ensure improved integration of the renewable energy generation into the grids and the electricity market. VPPs not only deal with the supply side, but also help manage demand and ensure reliability of grid functions through demand response (DR) and other load shifting approaches in real time. In this paper, utilizing a variety of distributed generation resources(such as emergency generator, commercial generator, energy storage device), activation scheme of the virtual power plant technology. In addition, through the analysis of the domestic electricity market, it describes a scheme that can be a virtual power plant to participate in electricity market. It attempts to derive the policy support recommendation in order to obtain the basics to the prepared in position of power generation companies for the commercialization of virtual power plant.

• International Journal of Advanced Culture Technology
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• v.12 no.2
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• pp.375-385
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• 2024

In the context of contemporary digital media, virtual influencers have become an increasingly important form of socialization and entertainment, in which emotional expression is a key factor in attracting viewers. In this study, we take Luo Tianyi, a Chinese virtual influencer, as an example to explore how emotions are expressed and perceived through facial expressions in different types of videos. Using Paul Ekman's Facial Action Coding System (FACS) and six basic emotion classifications, the study systematically analyzes Luo Tianyi's emotional expressions in three types of videos, namely Music show, Festivals and Brand Cooperation. During the study, Luo Tianyi's facial expressions and emotional expressions were analyzed through rigorous coding and categorization, as well as matching the context of the video content. The results show that Enjoyment is the most frequently expressed emotion by Luo Tianyi, reflecting the centrality of positive emotions in content creation. Meanwhile, the presence of other emotion types reveals the virtual influencer's efforts to create emotionally rich and authentic experiences. The frequency and variety of emotions expressed in different video genres indicate Luo Tianyi's diverse strategies for communicating and connecting with viewers in different contexts. The study provides an empirical basis for understanding and utilizing virtual influencers' emotional expressions, and offers valuable insights for digital media content creators to design emotional expression strategies. Overall, this study is valuable for understanding the complexity of virtual influencer emotional expression and its importance in digital media strategy.

• Journal of the Korean Operations Research and Management Science Society
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• v.36 no.4
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• pp.91-107
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• 2011

The importance of service industries is growing as the portion of the service sector increases fast in the recent decades. This research deals with service prototyping and testing in a service laboratory. While products are generally tested through prototyping in new product development processes, services are difficult to test because of the characteristic of service, intangibility. A service laboratory, named s-Scape, is the experiment environment which has been developed to test services in virtual space for the purpose of analysis and improvement of real-world services such as hospitals and automobile show rooms. In this research, we present a service prototyping tool and language to support service test in the service laboratory. We first analyze key elements of service prototypes, and then design the service prototype diagram (SPD) and the service prototype description language (SPDL). SPD, which is a variant of the service blueprint, is a graphical tool to be used to generate SPDL. SPDL is an executable language of describing a service prototype of a real-world service in extensible markup language (XML) to experiment the service environment in virtual space. SPD reflects the control and interface of virtual reality devices, as well as key elements of service modeling. SPD represents a service process in which service providers and customers interact with each other in a service scape.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.10-16
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• 2022

As an important part of virtual production, In-camera VFX is the process of shooting actual objects and virtual three-dimensional backgrounds in real-time through computer graphics technology and display technology, and obtaining the final film. In the In-camera VFX process, there are currently only two types of medium used to undertake background imaging, LED wall and chroma key screen. Among them, the In-camera VFX based on LED wall realizes background imaging through LED display technology. Although the imaging quality is guaranteed, the high cost of LED wall increases the cost of virtual production. The In-camera VFX based on chroma key screen, the background imaging is realized by real-time keying technology. Although the price is low, due to the limitation of real-time keying technology and lighting conditions, the usability of the final picture is not high. The short-throw projection technology can compress the projection distance to within 1 meter and get a relatively large picture, which solves the problem of traditional projection technology that must leaving a certain space between screen and the projector, and its price is relatively cheap compared to the LED wall. Therefore, in the In-camera VFX process, short-throw projection technology can be tried to project backgrounds. This paper will analyze the principle of short-throw projection technology and the existing In-camera VFX solutions, and through the comparison experiments, propose a low-cost solution that uses short-throw projectors to project virtual backgrounds and realize the In-camera VFX process.

• Journal of Computing Science and Engineering
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• v.5 no.4
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• pp.331-337
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• 2011

Recently, Virtual Desktop Infrastructure (VDI) has been widely adopted to ensure secure protection of enterprise data and provide users with a centrally managed execution environment. However, user experiences may be restricted due to the limited functionalities of thin clients in VDI. If thick client devices like laptops are used, then data leakage may be possible due to malicious software installed in thick client mobile devices. In this paper, we present Data Firewall, a security framework to manage and protect security-sensitive data in thick client mobile devices. Data Firewall consists of three components: Virtual Machine (VM) image management, client VM integrity attestation, and key management for Protected Storage. There are two types of execution VMs managed by Data Firewall: Normal VM and Secure VM. In Normal VM, a user can execute any applications installed in the laptop in the same manner as before. A user can access security-sensitive data only in the Secure VM, for which the integrity should be checked prior to access being granted. All the security-sensitive data are stored in the space called Protected Storage for which the access keys are managed by Data Firewall. Key management and exchange between client and server are handled via Trusted Platform Module (TPM) in the framework. We have analyzed the security characteristics and built a prototype to show the performance overhead of the proposed framework.

• Nuclear Engineering and Technology
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• v.52 no.5
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• pp.956-963
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• 2020

Dose optimization for Radioactive Occupational Personal (ROP) is an important subject in nuclear and radiation safety field. The geometric environment of a nuclear facility is complex and the work area is radioactive, so traditional navigation model and radioactive data field cannot form an effective environment model for dose assessment and dose optimization. The environment model directly affects dose assessment and indirectly affects dose optimization, this is an urgent problem needed to be solved. Therefore, this paper focuses on an environment model used for Dose Assessment and Dose Optimization (DA&DO). We designed a multi-layer radiation field coupling modeling method, and then explored the influence of the environment model to DA&DO by virtual simulation. Then, a simulation test is done, the multi-layer radiation field coupling model for nuclear facilities is demonstrated to be effective for dose assessment and dose optimization through the experiments and analysis.

• Korean Journal of Optics and Photonics
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• v.14 no.3
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• pp.249-254
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• 2003

In this paper, we propose an improved image encryption and decryption method using a phase-encoded virtual image and interference. An original image is simply decrypted by interfering a reference wave with the wave passing through a decrypting key and the encrypted image, where every image has grey level. The proposed encryption is performed by the multiplication of an encrypting key and a phase-encoded virtual image which dose not contain any information for the original image. Therefore even if unauthorized people analyze the encrypted image, they cannot reconstruct the original image. Also grey image encryption can improve the encryption level compared to binary image encryption. Computer simulation and optical experiments confirmed that the proposed technique is a simple for optical encryption.

• International Journal of Contents
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• v.10 no.3
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• pp.64-72
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• 2014

This study explored the elements that affect team achievements in virtual environments. In this study, consideration was given to the role of group dynamics in facilitating productive interaction. We aspired to reveal the mechanisms of group dynamics and examined how group dynamics affected team achievements in virtual environments. The empirical study was performed with undergraduate students enrolled in an e-learning course. In collaboration with other majors, students executed team projects and managed project issues in forums or chat rooms. The results of the empirical study indicated that leadership, creative friction, and group cohesion (components of group dynamics) had positive relationships with team achievements. The findings confirmed that addressing creative conflict is a method to improve team performance and that leadership is a key factor in project teams.