• JSTS:Journal of Semiconductor Technology and Science
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• 제16권3호
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• pp.293-299
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• 2016

Recently, as IoT (Internet of Things) becomes more important, low cost implementation of sensor nodes also becomes critical issues for two well-known standards, IEEE 802.15.4 and IEEE 802.15.6 which stands for WPAN (Wireless Personal Area Network) and WBAN (Wireless Body Area Network), respectively. This paper presents the area-optimized AES-CCM (Advanced Encryption Standard - Counter with CBC-MAC) hardware security engine which can support both IEEE 802.15.4 and IEEE 802.15.6 standards. First, for the low cost design, we propose the 8-bit AES encryption core with the S-box that consists of fully combinational logic based on composite field arithmetic. We also exploit the toggle method to reduce the complexity of design further by reusing the AES core for performing two operation mode of AES-CCM. The implementation results show that the total gate count of proposed AES-CCM security engine can be reduced by up to 42.5% compared to the conventional design.

• International Journal of Computer Science & Network Security
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• 제22권1호
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• pp.255-261
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• 2022

Routing Protocol for Low-Power and Lossy Networks (RPLs) in Internet of Things (IoT) is currently one of the most popular wireless technologies for sensor communication. RPLs are typically designed for specialized applications, such as monitoring or tracking, in either indoor or outdoor conditions, where battery capacity is a major concern. Several routing techniques have been proposed in recent years to address this issue. Nevertheless, the expansion of the network lifetime in consideration of the sensors' capacities remains an outstanding question. In this research, aANN-CUCKOO based optimization technique is applied to obtain a more efficient and dependable energy efficient solution in IOT-RPL. The proposed method uses time constraints to minimise the distance between source and sink with the objective of a low-cost path. By considering the mobility of the nodes, the technique outperformed with an efficiency of 98% compared with other methods. MATLAB software is used to simulate the proposed model.

• 마이크로전자및패키징학회지
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• 제27권3호
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• pp.73-76
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• 2020

은 나노와이어는 금속 특유의 고전도 특성, 낮은 Percolation threshold 및 고투과 특성을 나타내어 차세대 투명전극 물질로 각광받고 있다. 이를 플렉서블 및 웨어러블 디바이스, 전자피부 디바이스 등과 같은 다양한 분야에 활용하기 위해서는 은 나노와이어 전극을 필요한 형태로 패터닝 하기 위한 기술이 필수적으로 요구된다. 일반적으로, 은 나노와이어를 패터닝하기 위한 공법으로는 포토리소그래피 및 에칭, 프린팅, 레이저 Ablation 등을 들 수 있으나, 이러한 패터닝 기술들은 공정 절차가 복잡하거나 높은 공정 비용 등의 단점이 있다. 이에 본 연구에서는 UV-curable 점착제 기반의 low-cost 은 나노와이어 패터닝 공법을 개발하고자 하였다. 은 나노와이어 네트워크가 형성된 폴리우레탄 필름에 UV 경화형 테이프를 부착하고, UV를 선택적으로 조사한 뒤, 다시 UV 경화형 테이프를 벗겨내는 3단계의 간단한 공정만으로 은 나노와이어 패턴을 성공적으로 형성할 수 있었으며, 간단한 구현 원리 및 분석 결과를 본 논문에서 보고하고자 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권3호
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• pp.243-257
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• 2010

Rapid developments in wireless sensor networks have extended many applications, hence, many studies have developed wireless sensor network positioning systems for indoor environments. Among those systems, the Global Position System (GPS) is unsuitable for indoor environments due to Line-Of-Sight (LOS) limitations, while the wireless sensor network is more suitable, given its advantages of low cost, easy installation, and low energy consumption. Due to the complex settings of indoor environments and the high demands for precision, the implementation of an indoor positioning system is difficult to construct. This study adopts a low-cost positioning method that does not require additional hardware, and uses the received signal strength (RSS) values from the receiver node to estimate the distance between the test objects. Since many objects in indoor environments would attenuate the radio signals and cause errors in estimation distances, knowing the path loss exponent (PLE) in an environment is crucial. However, most studies preset a fixed PLE, and then substitute it into a radio propagation loss model to estimate the distance between the test points; such method would lead to serious errors. To address this problem, this study proposes a Path Loss Exponent Estimation Algorithm, which uses only four beacon nodes to construct a radio propagation loss model for an indoor environment, and is able to provide enhanced positioning precision, accurate positioning services, low cost, and high efficiency.

• 대한건축학회논문집:구조계
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• 제36권3호
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• pp.147-157
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• 2020

With the increasing obligation to reduce greenhouse gas emissions to the building sector, the government has been gradually expanding its obligation to zero-energy buildings since 2020. Since the ZEB certification took effect in 2017, 48 preliminary and main certifications have been completed as of March 2019, and most of them are public buildings or even certified, but have earned Grade 5 of ZEB. This means that compared with the number of annual building permits registered in Korea, the figure is insignificant, and that it receives little if not mandatory. Therefore, this study investigated empirical cases of ZEB additional construction cost and conducted cost benefit analysis according to changes in ZEB additional construction cost based on a preliminary feasibility analysis project recently conducted by the KDI. In addition, considering the public buildings, the social costs were considered, and the cost-benefit analysis method was the same as the KDI's preliminary feasibility analysis method. The analysis shows that if the ratio of ZEB additional construction cost is more than 5 percent, it is analyzed that there is no economic feasibility, and considering that the ratio of additional construction cost in the cases of ZEB in Korea is 17 percent to 38 percent, it will not be easy to obtain ZEB certification in terms of cost. Finally, to narrow these differences in cost and economic aspects, the overseas low energy and ZEB incentive examples proposed measures such as the concept of subsidy payment in Illinois and the compensation of social costs to private ZEB.

• 한국정보전자통신기술학회논문지
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• 제12권6호
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• pp.554-560
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• 2019

본 연구에서는 소프트웨어 신뢰성 분야에서 많이 사용하는 유한고장 NHPP Rayleigh 분포 모형과 NHPP Inverse Rayleigh 분포 모형을 소프트웨어 개발비용 모형에 적용한 후, 개발비용과 최적의 방출시간에 대한 속성을 비교, 분석하였다. 소프트웨어 개발비용의 속성을 분석하기 위하여 소프트웨어 고장시간 자료를 사용하였고, 모수추정은 최우추정법을 적용하였으며, 비선형 방정식은 이분법을 사용하여 계산하였다. 그 결과, Rayleigh 모형이 Inverse Rayleigh 모형보다 소프트웨어 개발비용이 비교적 적고, 소프트웨어 방출시점도 빨라서 상대적으로 우수한 모형임을 확인할 수 있었다. 본 연구를 통하여 기존 연구사례가 없는 Rayleigh 모형과 Inverse Rayleigh 모형의 개발비용 속성을 새롭게 분석하였으며, 더불어 소프트웨어 개발자들이 소프트웨어 신뢰도 향상 방법 및 개발비용의 속성을 탐색하는 데 필요한 기본지침으로 활용할 수 있을 것으로 기대한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1102-1105
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• 2004

In this paper, the problem of a viewer's head tracking in a desktop-based interactive stereoscopic display system is considered. A fast and low-cost approach to the problem is important for such a computing environment. The system under consideration utilizes a shuttle glass for stereoscopic display. The proposed method makes use of an image taken from a single low-cost video camera. By using a simple feature extraction algorithm, the obtained points corresponding to the image of the user-worn shuttle glass are used to estimate the glass center, its local 'yaw' angle, as measured with respect to the glass center, and its global 'yaw' angle as measured with respect to the camera location. With these estimations, the stereoscopic image synthetic program utilizes those values to interactively adjust the two-view stereoscopic image pair as displayed on a computer screen. The adjustment is carried out such that the so-obtained stereoscopic picture, when viewed from a current user position, provides a close-to-real perspective and depth perception. However, because the algorithm and device used are designed for fast computation, the estimation is typically not precise enough to provide a flicker-free interactive viewing. An error concealment method is thus proposed to alleviate the problem. This concealment method should be sufficient for applications that do not require a high degree of visual realism and interaction.

• 한국멀티미디어학회논문지
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• 제9권8호
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• pp.963-970
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• 2006

본 논문에서는 저가형 CSTN-LCD(Color Super-Twisted Nematic Liquid Crystal Display)에 사용하는 동영상 프로세서를 제안한다. 제안된 프로세서는 SFP(SubFrame Pattern) 기법을 적용하여 계조 확장을 할 뿐 아니라 플리커(flicker)현상을 제거하였고 BFI(Black Field Insertion) 기법을 적용하여 액정의 응답시간을 보상하였다. 그리고 화질 향상을 위한 에지 강조 기법과 보간기법을 적용하였다. 하드웨어 구조는 FPGA 프로토타입 보드를 사용하여 검증하였다. 제안된 동영상 프로세서는 PDA(Personal Digital Assistants), 모바일 폰과 PMP(Portable Multimedia Player) 등에 사용되어 질 수 있다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.117-120
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• 2004

As the maximum power operating point (MPOP) of photovoltaic (PV) power generation systems changes with varying atmospheric conditions such as solar radiation and temperature, an important consideration in the design of efficient PV system is to track the MPOP correctly. Although the efficiency of these Maximum Power Point Tracking algorithms is usually high, it drops noticeably in case of rapidly changing atmospheric conditions. This paper describes common MPPT control algorithm: Constant Voltage Control, Perturbation and Observation(P&O), Incremental Conductance (IncCnd) and proposes a new MPPT algorithm based on P&O algorithm. The conception and control principles of the proposed MPPT method are explained in detail and its validity of the proposed method is verified through several simulated results. As it doesn't use digital signal processor, this MPPT method has the merits of both a cost efficiency and a simple control circuit design. Therefore, it is considered that the proposed MPPT method is proper to low power, low cost PV applications.

• Advances in Computational Design
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• 제4권3호
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• pp.307-326
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• 2019

A low computational cost semi-analytical method is developed, based on eigenfunction expansion, to study the vibration of rectangular plates subjected to a series of moving sprung masses, representing a bridge deck under multiple vehicle or train moving loads. The dynamic effects of the suspension system are taken into account by using flexible connections between the moving masses and the base structure. The accuracy of the proposed method in predicting the dynamic response of a rectangular plate subjected to a series of moving sprung masses is demonstrated compared to the conventional rigid moving mass models. It is shown that the proposed method can considerably improve the computational efficiency of the conventional methods by eliminating a large number of time-varying components in the coupled Ordinary Differential Equations (ODEs) matrices. The dynamic behaviour of the system is then investigated by performing a comprehensive parametric study on the Dynamic Amplification Factor (DAF) of the moving loads using different design parameters. The results indicate that ignoring the flexibility of the suspension system in both moving force and moving mass models may lead to substantially underestimated DAF predictions and therefore unsafe design solutions. This highlights the significance of taking into account the stiffness of the suspension system for accurate estimation of the plate maximum dynamic response in practical applications.