• 응용통계연구
• /
• 제21권5호
• /
• pp.875-888
• /
• 2008

Hartigan과 Kleiner (1981, 1984)에 의해 제안된 모자이크 플롯은 범주형 자료의 탐색에 매우 유용한 시각화 도구이다. 모자이크 플롯은 범주 셀의 빈도를 사각형의 기에 비례하게 나타내므로 이해가 쉽고 데이터에 포함된 정보를 유지하지만 실제 모습은 변수 순서와 변수 내 범주의 순서에 따라 상당히 달라진다. 이에 우리는 본 연구에서 모자이크 플롯에서 크래머(Cramer)의 V 계수를 활용한 변수의 순서화 방법과 감마 계수를 활용한 범주의 순서화 방법을 제안하고 Titanic, Housing, PreSex 등 공개 자료에 적용한 결과를 제시한다.

• Transactions on Electrical and Electronic Materials
• /
• 제4권2호
• /
• pp.5-9
• /
• 2003

The liquid crystal (LC) aligning capabilities by the washing processes after rubbing on the two kinds of the rubbed polyimide (Pl) surface were studied. The polar anchoring energy of 4-n-pentyl-4'-cyanobiphenyl (5CB) increased with the rubbing strength RS on the two kinds of the rubbed PI surface. The polar anchoring energy of 5CB on the rubbed PI surface with alkyl side chains is larger than the rubbed PI surface with CONH moiety. Also, the surface ordering of 5CB on the rubbed PI surface with alkyl side chains is larger than the rubbed PI surface with CONH moiety. Therefore, the surface ordering of 5CB strongly depends on the polymers and washing process.

• 한국전자파학회논문지
• /
• 제22권7호
• /
• pp.705-710
• /
• 2011

본 논문에서는 Chase 알고리즘 기반의 연판정 e-BCH 복호시 계산량을 감소하는 알고리즘을 제시하였다. Chase 알고리즘 기반의 연판정 e-BCH 복호 방식은 test pattern을 만들기 위해 수신 데이터 중 신뢰성이 낮은 데이터를 순서대로 찾기 위해 ordering을 한다. 데이터를 ordering하는 과정과 test pattern 수 만큼을 수신 데이터와 비교함으로써 최적의 복호 열을 찾는 과정에서 높은 복잡도가 요구되며, 본 논문에서는 이러한 복잡도를 줄이는 방안을 제시하여 계산량 및 성능 관점에서 비교 분석하였다.

• 대한산업공학회지
• /
• 제3권1호
• /
• pp.39-47
• /
• 1977

Most of the current literature on inventory theory has been devoted to the study of single stage models. A class of inventory problems which is of great interest is the multistage inventory system which involves a series and hierarchical sequence of stations. This study analyzes some aspect of the series type and multi-stage inventory system, using the fixed cycle ordering which bas a modificatory control function in the system equations. The objective of this study is to clarify the dynamic behavior of the system. The author has derived the theoretical formulas of variation of ordering quantity and stock fluctuation of each stage due to power spectral density function. Influence of parameters such as, (1) intensity of autocorrelation of demand sequence ($\lambda$), (2) forecasting exponential smoothing factors of each stage (${\alpha}_1,\;{\alpha}_2,\;{\alpha}_3$) and (3) production control factor of the 3rd stage ($\gamma$), as operators of the system on the variation of ordering quantity and stock fluctuation of the system. is also clarified. As a result of this study, the relations between the variation of ordering quantity, stock fluctuation and the parameters of the system, have been found. The principles and the theorical analysis presented here will be applicable to more complex type of discrete control systems in constructing the specific condition of the system to minimize inventory variances.

• 한국분말재료학회지
• /
• 제13권2호
• /
• pp.112-118
• /
• 2006

[ $R_{1/3}Sr_{2/3}FeO_{3}$ ](R=Pr, Nd, and Sm) was synthesized and their magnetic properties and charge ordering(CO) transition related with lattice dynamics and oxygen vacancy were systematically investigated. The charge disproportion ation(CD) in $R_{1/3}Sr_{2/3}FeO_{3}$(R=Pr,Nd) was in which two kins of iron with valence state $Fe^{3+}$ and $Fe^{5+}$ were found with ratio of 2:1. In this charge ordering state a sequence of $Fe^{3+}Fe^{3+}Fe^{5+}Fe^{3+}Fe^{3+}Fe^{5+}$ exists aligned along the [111] direction of the pseudocubic perovskite structure. The charge ordering exist in distorted structure involving $t_{pd}$ hybridization. The disordering phases coexist in distorted structure as temprature in creases that is controlled amount of oxygen vacancy. The magnetic hyperfine fields indicate charge tranfering temperature as it dissapeared drastically.

• Applied Microscopy
• /
• 제28권1호
• /
• pp.121-126
• /
• 1998

Detailed studies of high resolution TEM inages on the modulated structure caused by Zn vacancy ordering along [110] direction in BZT sintered at $1400^{\circ}C$ for 90 hours had revealed that the images which had hexagonal patterns were similar to those obtained from the structure which had no modulation, These images had appeared over the wide ranges from -30 nm to -42 nm in defocus values and from 2 nm to 20 nm in thickness. The computer simulated images showed that the modulation due to Zn vacancy ordering had made a small change in contrast in the interior of hexagonal pattern, which was very difficult to differenciate in experiments. The image which demonstrated the modulated structure very well was the one which obtained at -52 nm in defocus value and 16 nm in thickness.

• 한국통신학회논문지
• /
• 제24권7A호
• /
• pp.1036-1045
• /
• 1999

본 논문에서는 임의의 프로세스가 여러 그룹에 속하는 중첩된 프로세스 그룹 환경에 효율적으로 적용할 수 있는 인과관계 순서화 알고리즘을 제시하였다. 본 알고리즘은 네트워크 구성 형태에 따라 선택할 수 있도록 제안하였다. 즉, 브로드캐스트 네트워크에서는 수신자 선택 알고리즘을 제안하였으며, 점대점 네트워크에서는 송신자 선택 알고리즘을 제안하였다. 각 알고리즘은 순서화에 요구되는 메시지 오버해드를 줄이기 위해 그룹별로 불필요한 벡터 타임스탬프를 제거하였으며, 메시지 오버해드를 최소화하기 위해 국부적으로 유지하고 있는 다른 프로세스와 다른 그룹의 정보를 이용하여 압축하도록 하였다. 각각의 새로운 인과관계 순서화 알고리즘을 논리적으로 증명하였고, 시뮬레이션을 통해 기존의 인과관계 순서화 알고리즘과의 성능을 비교하였다.

• 한국세라믹학회지
• /
• 제32권7호
• /
• pp.839-845
• /
• 1995

The structural and dielectric properties of Pb(Mg1/3Nb2/3)O3 ceramics substituted by Nd3+, La3+, K+ and Na+ were studied over 0~50 at.% substituent content. The 1 : 1 ordering behavior of Mg2+ and Nb5+ ions in the B site sublattice was observed in Nd3+-and La3+-modified compounds. The degree of ordering was increased with Nd3+, La3+ content in the compounds. But K+-or Na+-modified compounds did not exhibit the ordering behavior. This was explained by charge and size effect of A and B site cations and oxygen vacancies. As the mole fractions of substituent increased, the maximum values of dielectric constants were rapidly decreased and the phase transitions were broadened. Phase transition temperature was correlated with the covalency of A-O and B-O bonding.

• Journal of Magnetics
• /
• 제18권4호
• /
• pp.412-416
• /
• 2013

FePt:Ag (100 nm) nanocomposite thin films were prepared on naturally-oxidized Si substrates by dc magnetron sputtering at room temperature. X-ray diffraction (XRD) and transmission electron microscopy (TEM) are used to investigate the effects of annealing pressures on the ordering processes and microstructures of these films. The average sizes for the $L1_0$ ordered domains and the FePt grains are reduced to d = 9 nm and D = 13 nm from d = 19 nm and D = 34 nm, respectively, when the annealing pressure is enhanced to 0.6 GPa from room pressure at 873 K. Furthermore, the size distribution is improved into a narrow range. With increasing pressure, the coercivity of $L1_0$-FePt:Ag thin films decreases from 15.1 to 7.6 kOe. In the present study, the effects of high pressure on the $L1_0$ ordering processes and microstructures of FePt:Ag nanocomposite films were discussed.

• 한국시뮬레이션학회논문지
• /
• 제20권2호
• /
• pp.19-27
• /
• 2011

본 연구에서는 스무딩된 주문정책이 리드타임, 만족율, 재고비용에 미치는 영향을 연구한다. 이를 위해 스무딩된 order up to 주문정책을 사용하는 하류업체와 make to order 방식을 사용하는 상류업체로 구성된 공급사슬을 사용한다. 스무딩을 하면 리드타임이 예상하는 바와 같이 감소된다. 그러나 스무딩에 의해 하류업체에서의 만족율이 감소하며 재고비용이 증가된다. 한편 상류업체 제조시간의 분산이 평균 제조시간보다 만족율 및 재고비용에 미치는 영향이 더 크므로, 상류업체 제조시간의 변동성을 최소화해야 한다.