• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.3
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• pp.1047-1062
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• 2022

Differential power analysis (DPA) is disturbed by ghost peaks. There is a phenomenon that the mean absolute difference (MAD) value of the wrong key is higher than the correct key. We propose a compressed key guessing space (CKGS) scheme to solve this problem and analyze the AES algorithm. The DPA based on this scheme is named CKGS-DPA. Unlike traditional DPA, the CKGS-DPA uses two power leakage points for a combined attack. The first power leakage point is used to determine the key candidate interval, and the second is used for the final attack. First, we study the law of MAD values distribution when the attack point is AddRoundKey and explain why this point is not suitable for DPA. According to this law, we modify the selection function to change the distribution of MAD values. Then a key-related value screening algorithm is proposed to obtain key information. Finally, we construct two key candidate intervals of size 16 and reduce the key guessing space of the SubBytes attack from 256 to 32. Simulation experimental results show that CKGS-DPA reduces the power traces demand by 25% compared with DPA. Experiments performed on the ASCAD dataset show that CKGS-DPA reduces the power traces demand by at least 41% compared with DPA.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.4 no.1
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• pp.9-15
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• 2023

We analyzed data of endangered mammals in the 1st grade zone of the Ecological and Natural Map of Korea that were obtained through 202 field surveys over six years. Five endangered mammal species were identified including otters, long-tailed gorals, martens, leopard cats, and flying squirrels. The total number of habitat traces collected was 918, of which 897 traces (97.7%) were excrement types. The total surveyed distance was 697.7 km and there were 2,184 grids of 250×250 m each. Of these grids, 441 or 20.2% were confirmed as habitats of endangered mammals. Moreover, we analyzed results of repeated surveys in the same area by converting them into individual one-time surveys, accounting for 23.1% of the total area. The flying squirrel showed a low correlation with the frequency of field surveys but showed many habitats in a specific season. Leopard cats and martens were correlated with the frequency of field surveys. Results of analysis confirm that the grid method used for establishing the Ecological and Natural Map is unsuitable for the habitat division of flying squirrels, otters, leopard cats, and martens, and it does not reflect the actual habitats of these four species. Therefore, we propose that the concept of the habitat grid of species must be reevaluated and improved, specifically for endangered mammals.

• Journal of Photoscience
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• v.9 no.2
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• pp.359-361
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• 2002

A green mutant of Rhodobacter sphaeroides 60I was acquired by chemical induction. The blue-shifted of the carotenoid absorption was found in the Light-harvesting complex II (LH2) of the mutant. With the excitation at different wavelength, we observed that the evolution of excited-state dynamics in LH2 of Rhodobacter sphaeroides 60I. The dynamical traces demonstrate a dominant absorption followed concomitantly by an ultrafast transmission increase and decay with 818nm excitation.

• Journal of the Chungcheong Mathematical Society
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• v.30 no.2
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• pp.183-200
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• 2017

Zagier lift gives a relation between weakly holomorphic modular functions and weakly holomorphic modular forms of weight 3/2. Duke and Jenkins extended Zagier-lifts for weakly holomorphic modular forms of negative-integral weights and recently Bringmann, Guerzhoy and Kane extended them further to certain harmonic weak Maass forms of negative-integral weights. New Zagier-lifts for harmonic weak Maass forms and their relation with Bringmann-Guerzhoy-Kane's lifts were discussed earlier. In this paper, we give explicit relations between the two different lifts via direct computation.

• Journal of Korean Library and Information Science Society
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• v.31 no.1
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• pp.63-86
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• 2000

This essay traces the paths in which the writers have involved themselves in developing 'the studies of the present developmental stage' in their own field of studies, an by extension have become aware of the widespread presence of the discussion of decolonization in fields of social sciences. The present essay takes communication studies for a case of an indepth analysis of the effort toward academic self-reliance.

• Journal of the Korean Mathematical Society
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• v.37 no.6
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• pp.1031-1042
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• 2000

The equations prescribed in Ω⊂R(sup)n are called loaded, if they contain some operations of the traces of desired solution on manifolds (of dimension which is strongly less than n) from closure Ω. These equations result from approximations of nonlinear equations by linear ones, in the problems of optimal control when the control when the control actions depends on a part of independent variables, in investigations of the inverse problems and so on. In present work we study the nonlocal boundary value problems for first-order loaded differential operator equations. Criterion of unique solvability is established. We illustrate the obtained results by examples.

• Journal of the Korean Mathematical Society
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• v.33 no.4
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• pp.1039-1046
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• 1996

In the theory of partial differential equations with given initial values and boundary values one usually investigates to examine the well-posedness, that is, the unique existence of the solution as well as its continuous dependence on the data. This theory is strong enough for us to determine the situation anywhere and anytime provided that the initial data are actually given. However, in many cases the data are not completely known for us. Then in those situations arise the new problem to determine the unknown initial data by taking other conditions for the solutions.

• Korean Journal of Mathematics
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• v.22 no.3
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• pp.517-527
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• 2014

In this paper, we study affine transformations of normal bases and give an explicit formulation of the multiplication table of an affine transformation of a normal basis. We then discuss constructions of self-dual normal bases using affine transformations of traces of a type I optimal normal basis and of a Gauss period normal basis.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.4
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• pp.24-31
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• 2004

The objective of this work is to suggest a mastless pattern fabrication technique using the combination of machining by Nanoindenter(equation omitted) XP and HF wet etching. Sample line patterns were machined on a borosilicate surface by constant load scratch (CLS) of the Nanoindenter(equation omitted) XP with a Berkovich diamond tip, and they were etched in HF solution to investigate chemical characteristics of the machined borosilicate surface. All morphological data of scratch traces were scanned using atomic force microscope (AFM).

• Journal of Korea Technology Innovation Society
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• v.6 no.3
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• pp.306-327
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• 2003

The importance of technology assessment(TA) is increasingly emphasized, however, the question of what is TA is ambiguous yet. This article traces the concept of TA, and tries to identify the its meaning and current issues. It argues that the ambiguity of TA concept is not tragedy, but blessing in its growth. We came to know that one should consider for a successful TA some issues : institutional conditions, methodology, functions and timeliness. And they should also be considered in the TA-building process of Korea which is now on.