• Title/Summary/Keyword: Difference-in-Differences

Search Result 11,794, Processing Time 0.04 seconds

A Study of the shade of between maxillary and mandibular anterior teeth in the Korean (한국인의 상하악 전치부 색조에 관한 연구)

  • Kim, Tae-Jin; Kwon, Kung-Rock;Kim, Hyeong-Seob;Woo, Yi-Hyung
    • The Journal of Korean Academy of Prosthodontics
    • /
    • v.46 no.4
    • /
    • pp.343-350
    • /
    • 2008
  • Purpose: The purpose of this study was to spectrophotometrically evaluate the shade difference between of maxillary and mandibular anterior teeth in the Korean by the standard of vita classical shade guide using $SpectroShade^{TM}$. Material and methods: In this study, the shades of healthy anterior teeth were examined and analyzed using the digital shade analysis of $SpectroShade^{TM}$. This study examined 80 individuals in their twenties, thirties, fourties, fifities ages and 40 males and 40 females, presenting 12 healthy, unrestored maxillary and mandibular anterior teeth. Tooth brushing and oral prophylaxis were performed prior to evaluation. The $SpectroShade^{TM}$ was used to acquire images of the 12 maxillary and mandibular anterior teeth. These images were analyzed using $SpectroShade^{TM}$ Software, and shade maps of each tooth were acquired. The shade difference of upper and lower, and gender differences and ages difference were investigated and analyzed with CIE $L^{*}a^{*}b^{*}$ color order system. One-Way ANOVA test was used to find out if there were significant differences between groups tested and Sheffe multiple comparison was used to identify where the differences were. Results: 1. Shade differences were significant (P < .05) between maxillary and mandibular central incisor, lateral incisor, canine. 2. No significant differences in shade distribution were seen between lateral incisors and central incisors. 3. Canine's shade difference were more significant than central incisor's and lateral incisors's. 4. No significant differences in shade distribution were seen between genders in maxillary and mandibulr central incisor, lateral incisor, canine. 5. No significant differences in shade distribution were seen in order of years in maxillary and mandibulr central incisor, lateral incisor, canine. Conclusions: The results of this study show that 1. Shade difference was founded in maxillary and mandibular anterior teeth and ${\Delta}E^{*}$ value was more than 2.0. 2. Canine's shade difference were more significant than central incisor's and lateral incisors's and between central incisors and lateral incisors shade differences were no significant. 3. No significant differences in shade distribution were seen between genders in maxillary and mandibular anterior teeth. 4. No significant differences in shade distribution were seen in order of years grade in maxillary and mandibular anterior teeth.

Impact of Gender Differences in DNA on Consumer Buying Behavior

  • Kim, Young-Ei
    • Journal of Distribution Science
    • /
    • v.14 no.2
    • /
    • pp.33-39
    • /
    • 2016
  • Purpose The purpose of this study is to investigate the impact of gender differences in DNA on consumer buying behavior both online and offline and other buying channels to find out effective sales promotion strategies of enterprises. Research design, data, and methodology - This study investigated the relation between chromosome and DNA, DNA and gene, and gene and human behavior of gender. The study shows generic characteristics have influence upon consumers' buying behavior and inclination, and examined the effects of genetic characteristics depending upon the difference of gender DNA upon consumers' buying behavior. Results - Precedent studies on genetics and ethology showed close relations between chromosome and DNA, DNA and gene, and gene and buying behavior of the gene. 'Hunting and protection', one of the genetic characteristics in men's DNA, had great influence upon the consumers' different buying behavior. Conclusion - Gender DNA difference in genetics and ethology disclosed fundamental reasons for the difference in buying behavior and inclination of men and women. It gives implications that marketing strategies of advertising and sales promotion should be made in different ways depending upon men and women.

SEMI-DISCRETE CENTRAL DIFFERENCE METHOD FOR DETERMINING SURFACE HEAT FLUX OF IHCP

  • Qian, Zhi;Fu, Chu-Li
    • Journal of the Korean Mathematical Society
    • /
    • v.44 no.6
    • /
    • pp.1397-1415
    • /
    • 2007
  • We consider an inverse heat conduction problem(IHCP) in a quarter plane which appears in some applied subjects. We want to determine the heat flux on the surface of a body from a measured temperature history at a fixed location inside the body. This is a severely ill-posed problem in the sense that arbitrarily "small" differences in the input temperature data may lead to arbitrarily "large" differences in the surface flux. A semi-discrete central difference scheme in time is employed to deal with the ill posed problem. We obtain some error estimates which also give the information about how to choose the step length in time. Some numerical examples illustrate the effects of the proposed method.

Assessement of Consolidation Characteristics by Field Instrumentation (현장계측사례를 통한 압밀특성 평가)

  • Song, Jeong-Rak;Baek, Seung-Hun;O, Da-Yeong
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 1992.10a
    • /
    • pp.121-130
    • /
    • 1992
  • Assessement of comsolidation characteristics of soft soil is very important in the project of soft soil improvement. In the design step, the consolidation characteristics of soil is determined by the laboratory tests (typically oedometer test), generally. But there is big differences between the condition of laboratory test and the condition of field(in situ). the differences results in the considerable difference between the predicted and measured consolidation behavior. This article analyzed the consolidation data of the "SOFT SOIL IMPROVEMENT PROJECT of the 2nd Namdong Industrial Complex at Inchon". The project was improving the road way net work in the 2nd Namdong Industrial Complex by preloading and sand pile method. Field instrumentation was performed at 10 points which consist of pneumatic piezometers, magnetic probe extensometers, inclinometers and electronic dipmeter. The results showed that there is big difference in the laboratory predicted consolidation behavior and field consolidadion behavior. Also there was big difference in the settlement behavior and pore pressure behavior. This article investigated the above factors by comparing the settlement, pore pressure and strength at different conditions.onditions.

  • PDF

Gender Differences of Externalizing and Internalizing Behavior Problems According to the Extracurricular Education (사교육 시간에 따른 외현화 문제와 내면화 문제의 성별 차이)

  • Song, Jung-Eun;Jon, Duk-In;Soek, Jeong-Ho;Hong, Na-Rei;Kim, Young-Shin;Hong, Hyun-Ju
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
    • /
    • v.21 no.1
    • /
    • pp.37-44
    • /
    • 2010
  • Objectives : The purpose of this study was to evaluate gender differences with respect to the internalization or externalization of symptoms according to the amount of time spent engaged in extracurricular education. Methods : The study included a community sample of 755 boys and girls (mean age, 6.6 years), collected from five elementary schools in Gunpo, South Korea. Primary caregivers completed a questionnaire which included information on demographics, the amounts of time children spent in extracurricular education and with other activities, and an adapted form of the Behavior Assessment System for Children (BASC-2). Gender differences regarding externalizing and internalizing behavior problems were examined according to extracurricular education. Results : With respect to the boys, there was a difference in the frequency of those who had externalizing behavior problems according to their time spent in extracurricular education. In contrast, the girls exhibited no difference. With respect to those children who spent a lot of time engaged in extracurricular education, there was a gender-specific difference only with respect to externalizing behavior problems. Conclusion : A gender-specific difference exists only in terms of externalizing behavior problems according to time spent engaged in extracurricular education.

A study on reflective spectrum between In-Ceram alumina core and IPS Empress 2 core (In-Ceram Alumina Core와 IPS Empress 2 core의 분광반사율 연구)

  • Park, Myung-Ja;Kim, Joo-Won
    • Journal of Technologic Dentistry
    • /
    • v.23 no.2
    • /
    • pp.189-202
    • /
    • 2002
  • A study on reflective spectrum between In-Ceram alumina plate(IAP) and IPS empress 2 plate were carried out in order to determine the difference of reflective spectrum rates between materials and between thicknesses of materials(0.8mm, 1.0mm, 1.2mm) by visible wave. The rates are measured by spectrophotometer(Top scan model TC-1800). And an analysis of ANOVA and paired sample t-test were carried out. The results are summarized as follows. 1. The reflective rates of IAP and IPS increased slowly as visible wave spectrum increased. 2. The difference of reflective rates of IAP between 0.8mm and 1.0mm is significant but a little(less than 1%). The differences of reflective rates of IAP between 0.8mm and l.2mm and between 1.0mm and l.2mm are significant(8%, 10% ). 3. The differences of reflective rates of IPS between 0.8mm and 1.0mm and between 0.8mm and 1.2mm and between 1.0mm and 1.2mm are significant(0.06 %, 0.01 %, 2 %). 4. The differences of reflective rates of 0.8mm, 1.0mm between IAP and IPS are significant but a little(less than 0.9%, 0.5%). The difference of reflective rates of l.2mm between IAP and IPS is significant and larger than the other thicknesses relatively(7 %).

  • PDF

Multipath detection in carrier phase differential GPS

  • Seo, Jae-Won;Lee, Hyung-Keun;Lee, Jang-Gyu;Park, Chan-Gook
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 2005.06a
    • /
    • pp.1239-1243
    • /
    • 2005
  • A multipath mitigation method using the fault detection and isolation technique is proposed for the CDGPS. The base station is assumed to be immune to the effect of the multipath. With this reasonable assumption, the effect of multipath in moving station is mitigated. For that, the double difference measurement is produced, and then another additional difference between code pseudorange and acclumulated carrier phase is calculated. The test statistic is constituted with those differences. The hypothesis testing is applied to that test statistic. The proposed test statistic makes use of the effect of multipath in code pseudoranges and it does not use time differences. Therefore the detection ability for multipath is improved in most environments. However, the increased number of differences makes the measurement noises larger. The performance of the method is compared with that of the conventional parity space method with code pseudorange.

  • PDF

Relationship between Conformational Preferences and Torsional Parameters in Molecular Mechanics (MM3) Calculations

  • 조수경;박규순
    • Bulletin of the Korean Chemical Society
    • /
    • v.18 no.2
    • /
    • pp.143-149
    • /
    • 1997
  • We have investigated a relationship between conformational preferences of various substituents in monosubstituted cyclohexanes and pertinent torsional parameter values in molecular mechanics calculations. We have manipulated torsional parameters to supply a certain energy difference between gauche and anti conformers, and applied those parameters to monosubstituted cyclohexanes. After investigating 6 different substituents, namely Me, SiH3, F, Cl, Br, and I, MM3 calculations show that (1) the MM3 calculated A values with the current torsional parameters reproduce the available experimental values well, (2) the conformational energy difference between axial and equatorial conformations (the A value) correlates perfectly with the gauche/anti energy differences of the corresponding butane-like fragment (correlation coefficient=l.000), and (3) the A values are essentially twice as the gauche/anti energy differences (slopes=1.86-2.00). On the basis of our analysis, the A values as well as the gauche/anti energy differences are easily calibrated by an adjustment of the relevant torsional parameter. Thus, our technique for tuning the torsional parameters may be of great use in updating molecular mechanics results about conformational preferences whenever a further refinement is necessary.

Ethnic Difference in the Construction of War Bride Narrative: Velina Hasu Houston's Tea and Julia Cho's The Architecture of Loss

  • Hyeon, Youngbin
    • American Studies
    • /
    • v.44 no.2
    • /
    • pp.131-158
    • /
    • 2021
  • This paper examines how nation-specific history of Asian war brides affects different representations of war brides in Velina Hasu Houston's Tea (1984) and Julia Cho's The Architecture of Loss (2003). While war brides had long been excluded from American history, Japanese war brides were brought to public attention in the 1980s. Korean war brides, on the other hand, were kept out of sight until the 2000s. Focusing on how this time gap is related to ethnic difference, this paper analyzes dramaturgical differences between the two plays such as the presence/absence of war bride on stage or ethnic solidarity/familial reconciliation as the main device of war bride memorialization. Such differences, the paper suggests, stem from ethnic/historical differences between Korean and Japanese war brides. Through historical interpretations of the plays, this paper argues that America's military relationships with Korea and Japan were reproduced within the Asian-American families of each drama in ways that raise questions about pan-Asian identity.

Low Rayleigh Number Thermal Convection Between Two Horizontal Plates with Sinusoidal Temperature Distributions (정현적인 온도 분포를 갖는 두 수평 평판 사이에서의 작은 Rayleigh 수 열 대류)

  • 유주식;김용진
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.13 no.3
    • /
    • pp.145-152
    • /
    • 2001
  • Low Rayleigh number thermal convection in a fluid layer confined between two-infinite horizontal walls kept at spatially sinusoidal temperature distributions, T_L=T_m+\Delta T\sin \kappax,\;T_U=T_m+\Delta T\sin(\kappax-\beta)$, is theoretically investigated by a regular perturbation expansion method. For small wave numbers, an upright cell is formed between the two walls at $\beta$=0. The cell is tilted, as the phase difference increases, and a flow with tow counter-rotating eddies occurs at $\beta=\pi$. when the wave number is large, isolated eddies are formed near the lower and upper walls, for all the phase differences. There exists a wave number at which maximum heat transfer rate at the walls occurs, at each of the phase differences. And the wave number increases with increase of the phase difference. for a fixed wave number, the heat transfer rate decrease with increase of the phase difference.

  • PDF