• The Journal of Korean Institute of Next Generation Computing
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• v.13 no.2
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• pp.7-17
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• 2017

In this paper, we propose the TPS (TPM-enhanced Privacy Protection System) which is an automated privacy protection system enhanced with a TPM (Trusted Platform Module). The TPS detects documents including personal information by periodic scanning the disk of clients at regular intervals and encrypts them. Hence, system manages the encrypted documents in the server. In particular, the security of TPS was greatly enhanced by limiting the access of documents including the personal information with regard to the client in an abnormal state through the TPM-based platform verification mechanism of the client system. In addition, we proposed and implemented a VTF (Virtual Trusted File) interface to provide users with the almost identical user interface as general document access even though documents containing personal information are encrypted and stored on the remote server. Consequently, the TPS automates the compliance of the personal information protection acts without additional users' interventions.

• KIISE Transactions on Computing Practices
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• v.24 no.3
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• pp.129-137
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• 2018

NVMe(Non-Volatile Memory Express) SSD(Solid State Drive) is a high-performance storage that makes use of flash memory as a storage cell, PCIe as an interface and NVMe as a protocol on the interface. It supports multiple I/O queues which makes it feasible to process parallel-I/Os on multi-core environments and to provide higher bandwidth than SATA SSDs. Hence, NVMe SSD is considered as a next generation-storage for data-center and cloud computing system. However, in the virtualization system, the performance of NVMe SSD is not fully utilized due to the bottleneck of the software I/O stack. Especially, when it uses I/O stack of the hypervisor or the host operating system like Xen and KVM, I/O performance degrades seriously due to doubled-I/O stack between host and virtual machine. In this paper, we propose a new I/O engine, called Direct-AIO (Direct-Asynchronous I/O) engine, that can access NVMe SSD directly for I/O performance improvements on QEMU emulator. We develop our proposed I/O engine and analyze I/O performance differences between the existed I/O engine and Direct-AIO engine.

• Journal of IKEEE
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• v.12 no.4
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• pp.239-245
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• 2008

In this paper, a dc-dc power converter scheme with the FPGA based technology is proposed to apply for solar power system which has many features such as the good waveform, high efficiency, low switching losses, and low acoustic noises. The circuit configuration is designed by the conventional control type converter circuit using the isolated dc power supply. This new scheme can be more widely used for industrial power conversion system and many other purposes. Also, I proposed an efficient photovoltaic power interface circuit incorporated with a FPGA based DC-DC converter and a sine-pwm control method full-bridge inverter. The FPGA based DC-DC converter operates at high switching frequency to make the output current a sine wave, whereas the full-bridge inverter operates at low switching frequency which is determined by the ac frequency. As a result, we can get a 1.72% low THD in present state using linear control method. Moreover, we can use stepping control method, we can obtain the switching losses by Sp measured as 0.53W. This paper presents the design of a single-phase photovoltaic inverter model and the simulation of its performance.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.2
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• pp.99-104
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• 2011

In this paper, the intelligent landscape lighting power control and monitoring system with solar sell generator equipment is proposed. The first, the intelligent landscape lighting power controller is designed using the fuzzy logic control method. And the fuzzy logic controller is used to save power consumption for various reference intensity of the illumination. The second, the GUI monitoring system is presented. It has control and display faculty. And the practical experiment device is used to evaluate the performance criteria of the proposed intelligent landscape lighting power control system with the solar cell power generation equipment. From the experiment results, we present the property of proposed fuzzy controller such as steady state error, the tracking and power consumption characteristic for the reference intensity of illumination. And also we show the superiority of power control as well as the characteristic of GUI monitoring system in the proposed system.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.9
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• pp.638-643
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• 2003

Channel width dependence of hot-carrier effect in nMOSFET with shallow trench isolation is analyzed. $I_{sub}$- $V_{G}$ and $\Delta$ $I_{ㅇ}$ measurement data show that MOSFETs with narrow channel-width are more susceptible to the hot-carrier degradation than MOSFETs with wide channel-width. By analysing $I_{sub}$/ $I_{D}$, linear $I_{D}$- $V_{G}$ characteristics, thicker oxide-thickness at the STI edge is identified as the reason for the channel-width dependent hot-carrier degradation. Using the charge-pumping method, $N_{it}$ generation due to the drain avalanche hot-carrier (DAHC) and channel hot-electron (CHE) stress are compared. are compared.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.550-552
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• 2009

The negative bias temperature instability on LTPS TFTs in a darkened and an illuminated environment was investigated. Experimental results reveal that the generation of interface state density showed no change between the different NBTI stresses. The degradation of the grain boundary trap under illumination was more significant than for the darkened environment.

• International Journal of CAD/CAM
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• v.2 no.1
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• pp.29-37
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• 2002

De-manufacturing is an entire process of collecting, disassembling, reusing, refurbishing, recycling, and/or disposing products that are obsolete or un-repairable. Designing the products for inexpensive and efficient disassembly enhances the ease of de-manufacturing. Virtual disassembly addresses the difficulty and the methods to disassemble a product in design stage rather than really disassemble a product at the end of its life cycle. Based on the virtual disassembly analysis results, design will be improved for better assembling/disassembling. This paper presents a systematic virtual disassembly methodology such as disassembly relation modeling, path/sequence automatic generation and evaluation. This paper also presents a new virtual disassembly interface paradigm via virtual reality technology for disassembly simulation in virtual environment.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.51-53
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• 1994

Recently, advanced digital protection relays were developed in Japan. This improved relaying system for the next generation is expected to have higher performance for the discrimination of the fault, functions for multi-purpose use of acquired data, easy operation and maintance, and also have friendly man-machine interface. This paper describes the system configuration of the developed relay and its representive characteristics.

• Electronics and Telecommunications Trends
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• v.34 no.4
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• pp.108-116
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• 2019

Electro-active polymers and dielectric elastomers have many intriguing properties that enable smart interfaces and electrically tunable optical systems, such as haptic feedback devices, artificial muscles, and expansion-tunable optical elements. These device classes are of great interest owing to their promising roles in next-generation technologies including virtual or augmented reality, human sensing and muscular enhancement, and artificial skins. In this report, we review basic principles, current state-of-the-art techniques, and future prospects of electro-active and dielectric elastomer technology. We describe chemical and physical properties of the most promising polymer substances, essential elementary architectures for artificial muscle-like functionalities, and their applications to haptic interfaces, muscular enhancement, and focus-tunable optical elements.

• Archives of design research
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• v.17 no.4
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• pp.119-128
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• 2004

There is a lack of user centered design methods that support effective collaboration between designers and end-users for designing hardware and software integrated digital products. This paper presents the application of Collaborative Design and a new collaborative design prototyping tool for interactive digital product design projects. The tool consists of STCtools(State Transition Chart tools) software, hardware modeling materials, and physical interface toolkits for integrating software and hardware. STCtools allow users to create and edit States, to compose Events describing transitions between States, and to run intermediate or final results of STC. Using the hardware modeling materials and the physical interface toolkit, designers and end-users can collaborately examine the hardware and software integrated concepts in an early stage of the design process. Three collaborative design workshops of designing a portable digital guide for a theme park were accomplished to examine the feasibility of the tool. The results suggested that the tool supported iterative concept development and interactions between designers and end users. Although several user interface problems of STCtools were identified, the participants gave positive feedback on the role of the tool in collaborative concept generation and deployment. It is expected that the results of this study contribute not only to the collaboration between designers and end users, but also to the collaboration between designers, and between designers and other professionals.