• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.4
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• pp.943-949
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• 2017

Cryptography implementation over lightweight Internet of Things (IoT) device needs to provide an accurate and fast execution for high service availability. However, adversaries can extract the secret information from the lightweight device by analyzing the unique features of computation in the device. In particular, modern ARM Cortex-M3 processors perform the multiplication in different execution timings when the input values are varied. In this paper, we analyze previous multiplication methods over ARM Cortex-M3 and provide optimized techniques to accelerate the performance. The proposed method successfully accelerates the performance by up-to 28.4% than previous works.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.4A
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• pp.260-268
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• 2012

The use of an error-correcting code is essential in communication systems where the channel is noisy. Unless a receiver has accurate channel coding parameters, it becomes difficult to decode the digitized encoding bits correctly. In this paper, we propose two algorithms for reconstructing convolutional codes: one for general convolutional codes and the other for punctured convolutional codes. And we also verify the algorithms by performing intensive computer simulation in additive white gaussian noise (AWGN) channel.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.4
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• pp.1-6
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• 2012

This paper presents the extraction and analysis of small-signal parameters of tunneling field-effect transistors (TFETs) by using TCAD device simulation. The channel lengths ($L_G$) of the simulated devices varies from 50 nm to 100 nm. The parameter extraction for TFETs have been performed by quasi-static small-signal model of conventional MOSFETs. The small-signal parameters of TFETs with different channel lengths were extracted according to gate bias voltage. The $L_G$-dependency of the effective gate resistance, transconductance, source-drain conductance, and gate capacitance are different with those of conventional MOSFET. The $f_T$ of TFETs is inverely proportional not to $L_G{^2}$ but to $L_G$.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.4
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• pp.403-410
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• 1999

Mark point(Donghaksan) of Korean geodetic datum in Suwon could not be intervisible because of the development of the surroundings, so we were in a situation that we should establish new mark point and decide azimuth of the new mark point. Getting out of the intervisibility between control stations, refraction error and effect of illumination in urban area, our research team decided new azimuth of Suwon Geodetic Datum by GPS surveying for accuracy and economical efficiency. First we corrected and supplemented the specification on the decision of azimuth in accordance with our situation based on the study of foreign studies by using GPS, and we determined and analyzed the accuracy of the new azimuth through organizing and observing the GPS network.

• The KIPS Transactions:PartB
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• v.11B no.5
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• pp.537-544
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• 2004

The Web is rich with various sources of information. Due to the massive and heterogeneous web document collections, users want to find various types of target pages. Each type of information for Web search has designated queries. If a user query is not a designated query, then we cannot have good result documents. Different strategies are needed to utilize the goodness of each type of information for a search engine. If we know the property of information, then we can refine candidate pages and rank them delicately. Various experiments are conducted to show the properties of each type of information. Therefore, we show an appropriate combining formula to utilize the properties of each type of information. In addition, for a service finding task, we propose Service Link Information that utilizes the existence of mechanisms for a user interaction.

• The KIPS Transactions:PartB
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• v.15B no.3
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• pp.229-236
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• 2008

This paper examines effectiveness of using color images instead of grayscale ones for automatic lipreading. First, we show the effect of color information for performance of humans' lipreading. Then, we compare the performance of automatic lipreading using features obtained by applying principal component analysis to grayscale and color images. From the experiments for various color representations, it is shown that color information is useful for improving performance of automatic lipreading; the best performance is obtained by using the RGB color components, where the average relative error reductions for clean and noisy conditions are 4.7% and 13.0%, respectively.

• Journal of KIISE:Information Networking
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• v.33 no.1
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• pp.1-8
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• 2006

Security protocols have usually been developed using informal design and verification techniques. However, many security protocols thought to be secure was found to be vulnerable later. Thus, the importance of formal specification and verification for analyzing the safely of protocols is increasing. With the rise of mobile communication networks, various mobile security protocols have been proposed. In this paper, we identify the security weakness of the ASK mobile Protocol using formal verification technique. In addition, we propose a new ASK protocol modifying its vulnerability and verify its robustness.

• Korean Journal of Construction Engineering and Management
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• v.9 no.1
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• pp.66-76
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• 2008

Plant project is a complex project that consists of civil engineering, building, mechanical and electronic works. The schedule management is one of important factors in plant project because the construction duration of the project is very short comparing with the other construction projects. Specially, 4D CAD system needs to visualize construction schedule information in those complex projects. This study suggests methodologies for improving 4D CAD functions by considering those project characteristics. To develop a plant 4D CAD system, this study includes to develop new functions by analyzing actual schedule information from the plant construction sites.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.5
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• pp.373-381
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• 2020

Quadrotor is simple to model because of the symmetric structure but it has the disadvantage of being relatively sensitive to the external disturbance and system uncertainty. The PID technique applied for the attitude control of quadrotor has been applied comprehensively, but it has a disadvantage that is hard to precise control in the nonlinear system. In this work, a quadrotor attitude control law using the super twisting algorithm is studied, which has robust characteristics against disturbance and system uncertainty. To evaluate the attitude performance by the proposed technique, simulation studies and actual flight tests are carried out, and compared with the conventional PID controller.

• The KIPS Transactions:PartD
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• v.14D no.6
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• pp.649-656
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• 2007

Today, controller area network(CAN) is a field bus that is nowadays widespread in distributed embedded systems due to its electrical robustness, low price, and deterministic access delay. However, its use safety-critical applications has been controversial due to dependability limitation, such as those arising from its bus topology. Thus it is important to analyze the performance of the network in terms of load of data bus, maximum time delay, communication contention, and others during the design phase of the controller area network. In this paper, a simulation algorithm is introduced to evaluate the communication performance of the vehicle network and apply software base fault injection techniques. This can not only reduce any erratic implementation of the vehicle network but it also improves the reliability of the system.