• 대한전자공학회논문지TC
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• 제48권4호
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• pp.24-36
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• 2011

본 논문에서는 Arikan이 제안했던 극 부호의 부호화 및 복호화의 대수적 식을 개선하여 이진 이산 무기억 대칭 채널에서 연속 제거 복호 알고리즘을 이용한 극 부호의 채널의 합성과 분리를 확인했다. 이진 이산 무기억 대칭 채널 W에서 양극화 행렬 ${G_2}^{{\otimes}n}$을 통하여 블록 길이 $2^n$인 극 부호를 효과적으로 구성하여 정보 비트를 전송할 수 있다. 특히, $N{\geq}2$일 때, Arikan 부호의 복잡도 O($Nlog_2N$)이다. 극 부호가 향후 다중점 통신의 문제에 대한 하나의 대안이 될 수 있다는 것을 확인하였다.

• 한국컴퓨터그래픽스학회논문지
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• 제28권4호
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• pp.13-22
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• 2022

본 논문에서는 최소 입자 단위의 역동적인 회전 움직임을 나타낼 수 있는 MPM(Material Point Method) 기반 단일 프레임워크를 소개한다. 우리가 표현하고자 하는 입자는 다양한 형상(Shape)을 가질 수 있음과 동시에, 선형(Linear momentum), 회전(Angular momentum) 운동을 함께 묘사할 수 있다. 그 결과 기존 구형 입자의 선형 움직임만을 나타내던 입자 기반 시뮬레이션과는 달리, 시각적으로 단일 입자의 역동적인 모습을 표현할 수 있다. 제안하는 프레임워크는 회전 운동을 큰 변형(Large Deformation)으로부터 분해 및 추출 할 수 있다는 점에서 MPM을 활용하였다. 본 기법은 MPM 적분 과정 중 계산되는 변형 구배 텐서(Deformation Gradient Tensor)를 극 분해(Polar Decomposition)하는 과정을 통해 회전 텐서(Rotation Tensor)를 추출하고, 각 입자의 선형 운동과 함께 이를 적용하여 결과적으로 입자 자체의 회전, 선형 운동을 동시에 표현 하는 것이 가능하다. 본 연구에서는 제안하는 기법의 검증을 위해 바람에 흩날리며 회전하는 입자의 모습 및 움직이는 물체와 정지한 입자간의 상호작용 시뮬레이션을 기존 MPM을 이용한 시뮬레이션과의 비교를 통해 진행하였다.

• Ocean and Polar Research
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• 제25권1호
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• pp.53-62
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• 2003

Inductively coupled plasma mass spectrometry (ICP-MS) is useful instrument for determining abundance of rare earth elements, due to very low detection limits and rapid data acquisition. In this article, two methods are used for decomposition of alkaline rocks; close vessel acid digestion and $Na_2Co_3$ fusion. The two analytical results show good agreements. Considering total dissolved solids and detection limits, the most adequate dilution factor is 5,000 times. Polyatomic ion interferences during analysis can give rise to Inaccuracies. After correction from oxide and hydroxide interference, the analytical result show 20-30% decrease for Gd and Tm, 10-20% decrease for Tb and Er. In comparing the analytical results from KORDI with other institutes, most rare earth elements abundance show good agreements except Lu.

• 대한수학회지
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• 제44권1호
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• pp.25-34
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• 2007

An operator $T{\in}L(H)$ is said to be p-paranormal if $$\parallel{\mid}T\mid^pU{\mid}T\mid^px{\parallel}x\parallel\geq\parallel{\mid}T\mid^px\parallel^2$$ for all $x{\in}H$ and p > 0, where $T=U{\mid}T\mid$ is the polar decomposition of T. It is easy that every 1-paranormal operator is paranormal, and every p-paranormal operator is paranormal for 0 < p < 1. In this note, we discuss some properties for p-paranormal operators.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제15권1호
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• pp.93-101
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• 2008

In this article we shall characterize the Heinz-Kato-Furuta inequality in several ways, and the best bound for sharpening of the inequality is obtained by the method in [7].

• Journal of Ecology and Environment
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• 제46권4호
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• pp.282-291
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• 2022

Background: The Arctic permafrost stores enormous amount of carbon (C), about one third of global C stocks. However, drastically increasing temperature in the Arctic makes the stable frozen C stock vulnerable to microbial decomposition. The released carbon dioxide from permafrost can cause accelerating C feedback to the atmosphere. Soil organic matter (SOM) composition would be the basic information to project the trajectory of C under rapidly changing climate. However, not many studies on SOM characterization have been done compared to quantification of SOM stocks. Thus, the purpose of our study is to determine soil properties and molecular compositions of SOM in four different Arctic regions. We collected soils in different soil layers from 1) Cambridge Bay, Canada, 2) Council, Alaska, USA, 3) Svalbard, Norway, and 4) Zackenberg, Greenland. The basic soil properties were measured, and the molecular composition of SOM was analyzed through pyrolysis-gas chromatography/mass spectrometry (py-GC/MS). Results: The Oi layer of soil in Council, Alaska showed the lowest soil pH and the highest electrical conductivity (EC) and SOM content. All soils in each site showed increasing pH and decreasing SOC and EC values with soil depth. Since the Council site was moist acidic tundra compared to other three dry tundra sites, soil properties were distinct from the others: high SOM and EC, and low pH. Through the py-GC/MS analysis, a total of 117 pyrolysis products were detected from 32 soil samples of four different Arctic soils. The first two-axis of the PCA explained 38% of sample variation. While short- and mid-hydrocarbons were associated with mineral layers, lignins and polysaccharides were linked to organic layers of Alaska and Cambridge Bay soil. Conclusions: We conclude that the py-GC/MS results separated soil samples mainly based on the origin of SOM (plants- or microbially-derived). This molecular characteristics of SOM can play a role of controlling SOM degradation to warming. Thus, it should be further investigated how the SOM molecular characteristics have impacts on SOM dynamics through additional laboratory incubation studies and microbial decomposition measurements in the field.

• The Korean Journal of Ecology
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• 제17권4호
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• pp.501-511
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• 1994

Dynamics of nutrients, non-polar, water solubles, acid solubles and acid insolubles (lignin) in decomposing litter were investigated for 2 years in the oak, Quercus acutissima, and the pitch pine, Pinus rigida, stands in the vicinity of Kongju, Chungnam Province. Nitrogen and phosphorus conetrations in decomposing litter increased with time elapsed, however, potassium decreased rapidly within three months and then remined constant with time elapsed. Calcium concentration in needle litter during experimental period was lower than that of initial concentration in needle litter during experimental period was lower than that of initial concentration, and showed no significant variation with time elapsed. Calcium concentration in oak litter during the experimental period, however, were higher than that of initial concentration. Magnesium concentration in oak litter decreased repidly during six months, and then remaines constant thereafter. Annual amount of nitrogen, phosphorus, potassium, calcium and magnesium which returned to soil via litter decomposition in the oak and the pitch pine stands was $3.3g/m^2$ and $0.9g/m^2$ for N, $0.03g/m^2$ and $0.01g/m^2$ for P, $1.3g/m^2$ and $0.7g/m^2$ for K, $0.7g/m^2$ and $1.2g/m^2$ for Ca, $0.9g/m^2$ and $0.4g/m^2$ for Mg, respectively. Non-polar, and water- and acid-soluble fractions in decomposing litter decreased and lignin increased with time.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권10호
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• pp.553-558
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• 2000

This paper deals with change of contact angle, surface potential decay, surface resistivity and XPS of water-treated epoxy insulator. From the experimental results on the contact angle was reduced from $74^{\circ}$to $24^{\circ}$ due to the formation of polar hydroxyl groups on surface which was associated with intermolecular reaction between epoxy chains of three-dimensional network structure and water molecules. From the experimental results in the surface potential decay of water treated-samples, it was found that the accumulation of charge is decreased and the surface potential decay time is shortened by the interaction of polar hydroxyl groups induced on the treated surface as the increment of treatment time. The positive charging on the treated surface compared with negative charging is relatively lowered by the induction of polar hydroxyl groups. The surface resistivity was changed from $10^{15}[{\Omega}/cm^2$] to $10^{12}[{\Omega}/cm^2$] caused by water treatment. From XPS, it was found that the changes affected by the surface degradation of epoxy were caused by the generation of carboxyl groups through the chain decomposition and recombination with oxygen molecules in the air.

• Kyungpook Mathematical Journal
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• 제57권3호
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• pp.457-471
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• 2017

A necessary and sufficient condition for the product AB of a selfadjoint operator A and a bounded selfadjoint operator B to be normal is given. Various properties of the factors of the unitary polar decompositions of A and B are obtained in the case when the product AB is normal. A block operator model for pairs (A, B) of selfadjoint operators such that B is bounded and AB is normal is established. The case when both operators A and B are bounded is discussed. In addition, the example due to Rehder is reexamined from this point of view.

• Kyungpook Mathematical Journal
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• 제49권4호
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• pp.647-650
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• 2009

For a bounded operator T = $U{\mid}T{\mid}$ (polar decomposition), we consider a transform b $\widehat{T}$ = ${\mid}T{\mid}U$ and discuss the convergence of iterated transform of $\widehat{T}$ under the strong operator topology. We prove that such iteration of quasiaffine hyponormal operator converges to a normal operator under the strong operator topology.