• 한국통신학회논문지
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• 제37C권10호
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• pp.949-964
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• 2012

최근 악성코드 및 바이러스 등으로 사용자 PC가 위협받고 있다. 특히, 제로데이 공격 등 알려지지 않은 공격들이 끊임없이 나오고 있어, 사용자 PC는 더 이상 안전하다고 확신하기 어려운 환경이 되었다. 따라서 인터넷 서비스의 이용에 있어서, 안전성이 보장되지 않은 PC를 이용하는 사용자가 기존의 인증 프로토콜을 이용하여 사용자를 인증할 경우, 인증 정보의 도난 및 중간자 공격 등 다양한 위협을 받을 수 있다. 또한 메모리 해킹등과 같은 공격을 당할 경우, 사용자는 자신의 PC가 감염되었는지 인지하기조차 어려운 상황에 놓이게 된다. 따라서 본 논문은 QR-Code와 통신기능이 가능한 스마트 기기를 활용한 안전한 QR-Login 사용자 인증 프로토콜을 설계하고, 인터넷 서비스 이용 시 중요정보의 안전성 보증을 위한 방법을 제안한다. 제안된 방법을 통하여 사용자는 알려지지 않은 공격으로부터 PC가 위협받는 경우에도 사용자의 중요정보를 보호할 수 있고, 금융거래와 같은 민감한 거래 시에도 안전하게 거래를 할 수 있다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1993년도 춘계학술대회 논문집
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• pp.257-261
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• 1993

This paper presents a design method of turning device for robotic assembly based on the verification of a instability for a base assembly. To derive the instability, first we inference collision free assembly directions by extracting separable directions for the part, and calculate the separability which gives informations as to how the part can be dasily separated. Using the result, we determine the instability evaluated by summing the all separabilites of each component part in base assembly. The proposed method gives a design guidance of turning device by evaluating a degree of the motion istability for the base assembly in flexible manufacturing application. An example is given to illustrate the concepts and procedure of the proposed scheme.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.118.3-118
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• 2001

CLED (Contact Light Emitting Device) has three layers consisting of a transparent electrode, a light emitting layer and a substrate. When the substrate of the CLED comes in contact with a fingerprint under AC input voltage, it makes an electric field between the fingerprint and the device. Due to the electric field, the light is emitted along the ridgeline of the fingerprint. The intensity along the ridge on the surface of the CLED increase in proportion to the electric field. To achieve uniform performance of fingerprint verification devices, inspection system of CLED for quality control were required. In this research, we proposed the factors for quality controls such as dimensions of the CLED, uniformity ...

• 대한조선학회논문집
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• 제57권6호
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• pp.381-387
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• 2020

According to the increase of concern for environmental problems, the energy saving becomes an important issue because it is one of the most effective methods of decreasing CO2 which is major environmental problem. In the present study, the post device after propeller related with rudder has been focussed. Recently the full-spade twisted rudder has been frequently used not only to increase the efficiency but also to remove the cavitation risk on leading edge. In addition to that the rudder bulb is also applied to the rudder to increase the propulsion efficiency as well as to minimize the cavitation erosion risk around twisting part. The parametric study has been conducted for investigating the optimum configuration of twisting rudder with bulb by CFD. The present optimization has been applied to the KVLCC2 full-body ship. The verification of the computed results is also expected to be conducted by the comparison with experimental results in the near future.

• Journal of Ship and Ocean Technology
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• 제12권4호
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• pp.20-31
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• 2008

Development of rudder gap flow blocking device for lift augmentation and cavitation suppression is presented. In order to verify the performance of this device, cavitation visualization and surface pressure measurements were carried out in a cavitation tunnel. Numerical simulations were conducted using a computational fluid dynamics code for more rigorous verification. The new rudder system is equipped with cam devices, which effectively close the gap between the horn/pintle and movable wing parts. The experimental and computational results show that the proposed rudder system is superior to the conventional rudder systems in terms of the lift augmentation and cavitation suppression.

• International journal of advanced smart convergence
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• 제8권2호
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• pp.77-87
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• 2019

One of important concerns in information security is to control information flow. It is whether to protect confidential information from being leaked, or to protect trusted information from being tainted. In this paper, we present Piosk (Physical blockage of Information flow Kiosk) that addresses both the problems practically. Piosk can forestall and prevent the leakage of information, and defend inner tangible assets against a variety of malwares as well. When a visitor who carries a re-writable portable storage device, must insert the device into Piosk installed next to the security gate. Then, Piosk scans the device at the very moment, and detects & repairs malicious codes that might be exist. After that, Piosk writes the contents (including sanitized ones) on a new read-only portable device such as a compact disk. By doing so, the leakage of internal information through both insiders and outsiders can be prevented physically. We have designed and prototyped Piosk. The experimental verification of the Piosk prototype implementation reveals that, Piosk can accurately detect every malware at the same detection level as Virus Total and effectively prevent the leakage of internal information. In addition, we compare Piosk with the state-of-the-art methods and describe the special advantages of Piosk over existing methods.

• 한국군사과학기술학회지
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• 제24권2호
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• pp.204-210
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• 2021

In this paper, we studied a method of wirelessly checking up the POD for captive flight tests which is performed during the development of guided weapons systems. The wireless power transfer module, the power distribution device, and the battery pack were designed to wirelessly power the captive flight test POD, and the communication device was designed to enable wireless communication between the POD and the check-up device. The communication device was designed to enable WiFi, IR communication, and laser diode communication, so that various communication methods could be tested. Through the performance test, it was confirmed that power was stably supplied to the captive flight test POD, and the wireless communication performance was verified by measuring the delay time and error rate. As a result, by using our system the POD check-up for the captive flight test was performed wirelessly and the data of the captive equipment could be obtained effectively.

• 한국산학기술학회논문지
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• 제15권6호
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• pp.3858-3864
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• 2014

본 논문에서는 모바일 기반의 스마트 감성조명 제어 시스템을 제안한다. 감성조명 장치의 내부발열 및 전력소비를 감소시키기 위하여 제안된 스마트 감성조명 제어 시스템은 안드로이드 플랫폼 모바일 기기와 지그비 모듈, 감성조명 장치, 점등제어 모듈, 전원 공급기, 범용 트랜지스터로 구성하였다. 모바일 디바이스는 시스템에 연결될 때, 감성조명 장치에 실시간 제어 정보를 전송하고, 제어 메시지 및 상태 모니터링을 기반으로 감성조명 장치를 제어하도록 설계하였다. 본 논문에서 제안된 스마트 감성조명 제어 시스템의 효율성 검증 결과, 감성조명 제어 및 색온도 변수에 의해 제어가 가능하였다. 그리고 감성언어를 사용하여 가변적으로 점등제어하기 때문에 21%의 발열량 및 최대 48%의 소비 전력을 감소시켰다.

• Journal of Power Electronics
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• 제13권3호
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• pp.390-399
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• 2013

As a result of the depletion of fossil fuels and environmental contamination, it has become important to use renewable energy. For the stable utilization of renewable energy sources, energy storage devices must be used. In addition, renewable and distributed power sources with energy storage devices must operate stably under grid-connected mode. This paper proposed dynamic response modeling for renewable power generation systems including a charger/discharger with an energy storage device in order to derive a method to guarantee stable operation while fully utilizing the energy from the energy storage device. In this paper, the principle operation and design guidelines of the proposed scheme are presented, along with a performance analysis and simulation results using MATLAB and PSIM. Finally, a hardware prototype of a 1kW power conditioning system with an energy storage device has been implemented for experimental verification of the proposed converter system.

• 한국정밀공학회지
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• 제31권8호
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• pp.677-682
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• 2014

One of the most important element technologies for achieving high-precision in machine tool spindle systems is preload technology for the bearing of spindle systems. Fixed position preload, constant pressure preload, conversion preload and variable preload methods have been applied for the spindle systems. In this study, a new variable preload method using centrifugal force and rubber pressure is used for reducing installation costs through simplifying its structure. The main objective of the work is the verification of the operability in a preload device using the rubber pressure by the finite element analysis. It is shown that the variable preload device proposed in this study is applicable to high speed machine tool spindles.