• ETRI Journal
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• v.33 no.4
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• pp.611-620
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• 2011

Since card-type one-time password (OTP) generators became available, power and area consumption has been one of the main issues of hardware OTPs. Because relatively smaller batteries and smaller chip areas are available for this type of OTP compared to existing token-type OTPs, it is necessary to implement power-efficient and compact dedicated OTP hardware modules. In this paper, we design and implement a low-power small-area hardware OTP generator based on the Advanced Encryption Standard (AES). First, we implement a prototype AES hardware module using a 350 nm process to verify the effectiveness of our optimization techniques for the SubBytes transform and data storage. Next, we apply the optimized AES to a real-world OTP hardware module which is implemented using a 180 nm process. Our experimental results show the power consumption of our OTP module using the new AES implementation is only 49.4% and 15.0% of those of an HOTP and software-based OTP, respectively.

• Nuclear Engineering and Technology
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• v.52 no.10
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• pp.2394-2401
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• 2020

Octadecylamine is an effective film-forming amine that protects carbon steel from corrosion. In the present study, the effect of octadecylamine concentration on adsorption on a carbon steel surface was investigated in anaerobic alkaline solution by using SEM/EDS, TEM and the Materials Studio simulation techniques. TEM morphology observation and EDS elemental detection determine the thicknesses of octadecylamine film on a carbon steel surface, which are confirmed by the in-situ electrochemical impedance spectroscopy measurement and resistance calculation. The Materials Studio simulation reveals the number of octadecylamine film layers at different concentrations. Results obtained in this study indicate that adsorption of octadecylamine film on carbon steel proceeds with the multi-layer adsorption mechanism.

• The Korean Journal of Pain
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• v.2 no.1
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• pp.97-99
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• 1989

Epidural block is used extensively in each of the fields of surgical anesthesia, obstetric anesthesia, and diagnosis and management of acute and chronic pain. New developments in the understanding of pain conduction have extended the use of continuous epidural blockade to the administration of drugs that selectively block pain conduction while leaving sensation and motor power essentially unchanged. The safety and the reliability of spinal epidural catheter techniques have permitted relief of acute and chronic pain. However, one of the important aspects of the management of the epidural catheter is the possibility of epidural infection. We have experienced a case of epidural infection during control of post-herpetic neuralgia and discuss management of the epidural catheter in this article.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1964-1969
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• 2008

A railway is a complex system integrated with a lot of technical elements such as rolling stock, power, signal control, communications, tracks, stations, operation control systems, and so on. As a mass transportation system, a railway could contain potential risks that may result in a high death rate and property losses. Accordingly, Railroad Safety Technology R&D Corps. is adopting the plan of the construction of Railway Safety Test Facilities as a part of the Railway Total Safety Project to enhance the railway safety, and carrying out researches on effective project management methods with Systems Engineering techniques. To support that, we propose the more effectual management method of constructing the Railway Safety Test Facilities applying the model-based systems engineering tool to the research.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.9
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• pp.76-80
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• 2007

For a more efficient and economical management of substations of power system areas, the concept of substation automation has been introduced using intelligent and ubiquitous IT techniques. In this paper, ubiquitous IT prototype hardware, functions and communication interfaces on an embedded platform for substation automation are proposed. Also, operating system architecture is suggested for the effective implementation of substation automation.

• Journal of Semiconductor Engineering
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• v.1 no.2
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• pp.64-73
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• 2020

As CMOS technology scales down, the design of analog signal processing circuit becomes far more difficult because of steadily decreasing supply voltage and smaller intrinsic gain of transistors. With sub-1V supply voltage, the conventional analog signal processing relying on high-gain amplifiers is not an effective solution and different approach has to be sought. One of the promising approaches is "time-domain analog signal processing" which exploits the improving switching speed of transistors in a scaled CMOS technology. In this paper, various time-domain analog signal processing techniques are explained with some experimental results.

• Journal of the Korean Operations Research and Management Science Society
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• v.41 no.3
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• pp.45-58
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• 2016

Data are important in an organization because they are used in making decisions and obtaining insights. Furthermore, given the increasing importance of data in modern society, data governance should be requested to increase an organization's competitive power. However, data governance concepts have caused confusion because of the myriad of guidelines proposed by related institutions and researchers. In this study, we re-established the concept of ambiguous data governance and derived the top-level components by analyzing previous research. This study identified the components of data governance and quantitatively analyzed the relation between these components by using DEMATEL and context analysis techniques that are often used to solve complex problems. Three higher components (data compliance management, data quality management, and data organization management) and 13 lower components are derived as data governance components. Furthermore, importance analysis shows that data quality management, data compliance management, and data organization management are the top components of data governance in order of priority. This study can be used as a basis for presenting standards or establishing concepts of data governance.

• Journal of Korean Society of Disaster and Security
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• v.14 no.2
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• pp.35-42
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• 2021

In order to produce electric vehicle demand forecasting information, which is an important element of the plan to expand charging facilities for electric vehicles, a model for predicting electric vehicle demand was proposed using Exponential Smoothing. In order to establish input data for the model, the monthly power demand of cities and counties was applied as independent variables, monthly electric vehicle charging stations, monthly electric vehicle charging stations, and monthly electric vehicle registration data. To verify the accuracy of the electric vehicle power demand prediction model, we compare the results of the statistical methods Exponential Smoothing (ETS) and ARIMA models with error rates of 12% and 21%, confirming that the ETS presented in this paper is 9% more accurate as electric vehicle power demand prediction models. It is expected that it will be used in terms of operation and management from planning to install charging stations for electric vehicles using this model in the future.

• Journal of IKEEE
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• v.22 no.1
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• pp.174-179
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• 2018

In this paper, design of high-efficiency DC-DC converter is presented for low-power PMIC (power management integrated circuit). As PMIC technologies for IoT and wearable devices have been continuously improved, high-efficiency energy harvesting schemes should be essential. Since the supply voltage resulting from energy harvesting is low and widely variable, design techniques to achieve high efficiency over a wide input voltage range are required. To obtain a constant switching frequency for wide input voltage range, frequency compensation circuit using supply-voltage variation sensing circuit is included. In order to obtain high efficiency performance at very low-power condition, accurate burst-mode control circuit was adopted to control switching operations. In the proposed DC-DC buck converter, output voltage is set to be 0.9V at the input voltage of 0.95~3.3V and maximum measured efficiency is up to 78% for the load current of 180uA.

• Nuclear Engineering and Technology
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• v.16 no.4
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• pp.181-194
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• 1984

The in-core fuel management problem was studied by use of the calculus of variations. Two functions of interest to a public power utility, the profit function and the cost function, were subjected to the constraints of criticality, the reactor turnup equations and an inequality constraint on the maximum allowable power density. The variational solution of the initial profit rate demonstrated that there are two distinct regions of the reactor, a constant power region and a minimum inventory or flat thermal flux region. The transition point between these regions is dependent on the relative importance of the profit for generating power and the interest charges for the fuel. The fuel cycle cost function was then used to optimize a three equal volume region reactor with a constant fuel enrichment. The inequality constraint on the maximum allowable power density requires that the inequality become an equality constraint at some points in the reactor. and at all times throughout the core cycle. The finite difference equations for reactor criticality and fuel burnup in conjunction with the equality constraint on power density were solved, and the method of gradients was used to locate an optimum enrichment. The results of this calculation showed that standard non-linear optimization techniques can be used to optimize a reactor when the inequality constraints are properly applied.