• 한국구조물진단유지관리공학회 논문집
• /
• 제5권4호
• /
• pp.169-176
• /
• 2001

This study aims to present a more reasonable control value than the exiting one by comparing and analyzing control values and field instrument8tion values of the whole excavation depth of the four case sites, using geometric averaging as a statistical method. The range of the study is confined to the horizontal displacement of braced excavation walls among a variety of items, prescribed in the control values by approximately of the allowable and design values, and by safety factors. As a result, it is desirable to revise 70, 90, and 100 percent of LEVEL I, II, and III, respectively. The horizontal displacement values of the allowable and design values approximations should change to 104, 133, and 148 percent of the allowable and design values, respectively. In addition, modifying the horizontal displacement control value of the braced excavation walls is not needed. The horizontal displacement value, presented in the control value as a safety factor, is now 1.19, as it has a slight difference from the present value.

• 국제학술발표논문집
• /
• The 6th International Conference on Construction Engineering and Project Management
• /
• pp.658-659
• /
• 2015

GCM and scenario uncertainties are first investigated for 5 major watersheds (Han River, Paldang dam, Namhan River, Bukhan River and Imjin River watersheds). As a result of this study, it is found that CCSM3-based annual precipitation increases linearly with respect to the 10-year moving average values while CSIRO-based precipitation does not show much of trend. The results from annual DJF mean precipitation show a similar trend with respect to their 10-year moving average values. Both CCSM3- and CSIRO-based annual JJA mean precipitation do not show much of trend toward 21^st century. In general, CCSM3-based precipitation values are slightly higher than CSIRO-based values with respect to their annual and annual JJA mean precipitation values, but CSIRO-based annual DJF mean precipitation values are slightly higher than CCSM3-based values. In case of mean air temperature between CCSM3 and CSIRO during 21^st century, all of results show a clear trend in warming with the passage of time for 5 watersheds. However the upward trends from CCSM3-based values slow down toward end of 21^stcentury while CSRIO-based values increases almost linearly.

• 한국기후변화학회지
• /
• 제6권4호
• /
• pp.331-344
• /
• 2015

A long-term gridded historical data at 3 km spatial resolution has been generated for practical regional applications such as hydrologic modelling. However, overly high or low values have been found at some grid points where complex topography or sparse observational network exist. In this study, the Inverse Distance Weighting (IDW) method was applied to properly smooth the overly predicted values of Improved GIS-based Regression Model (IGISRM), called the IDW-IGISRM grid data, at the same resolution for daily precipitation, maximum temperature and minimum temperature from 2001 to 2010 over South Korea. We tested various effective distances in the IDW method to detect an optimal distance that provides the highest performance. IDW-IGISRM was compared with IGISRM to evaluate the effectiveness of IDW-IGISRM with regard to spatial patterns, and quantitative performance metrics over 243 AWS observational points and four selected stations showing the largest biases. Regarding the spatial pattern, IDW-IGISRM reduced irrational overly predicted values, i. e. producing smoother spatial maps that IGISRM for all variables. In addition, all quantitative performance metrics were improved by IDW-IGISRM; correlation coefficient (CC), Index Of Agreement (IOA) increase up to 11.2% and 2.0%, respectively. Mean Absolute Error (MAE) and Root Mean Square Error (RMSE) were also reduced up to 5.4% and 15.2% respectively. At the selected four stations, this study demonstrated that the improvement was more considerable. These results indicate that IDW-IGISRM can improve the predictive performance of IGISRM, consequently providing more reliable high-resolution gridded data for assessment, adaptation, and vulnerability studies of climate change impacts.

• Bulletin of the Korean Chemical Society
• /
• 제31권8호
• /
• pp.2357-2360
• /
• 2010

Kinetic studies on the pyridinolysis of aryl dithiocyclopentanecarboxyaltes 2 were carried out at $60.0^{\circ}C$ in acetonitrile. In the aminolysis of 2, the $\beta_X$ values were 0.5 - 0.8 with anilines, and there was no breakpoint. However, in the pyridinolysis of 2, biphasic Bronsted plots were obtained, with a change in slope from a large value ($\beta_X{\cong}0.7$) to a small value ($\beta_X{\cong}0.4$) at $pK_{a}^0$ = 5.2. This was attributed to a change in the rate-limiting step from breakdown to the formation of a zwitterionic tetrahedral intermediate, $T^{\pm}$, in the reaction path, with an increase in the basicity of the pyridine nucleophile. An obvious change in the cross-interaction constant ${\rho}_{XZ}$ from a large positive ($\rho_{XZ}$ = +1.02) value to a small negative value (${\rho}_{XZ}$ = -0.17) supports the proposed mechanistic change.

• 한국광학회지
• /
• 제7권3호
• /
• pp.219-226
• /
• 1996

빛의 입자 파동 이중성을 수용하는 양자 광학은 때때로 파동성에만 바탕을 둔 고전 광학과 상이한 결과를 보여준다. 본 논문에서는 빛이 빛살 가르개를 통과하면서 그 세기와 위상에 대한 요동이 어떻게 변화하는가를 고찰하고 고전 이론과 양자 이론이 보이는 차이점을 기술하였다. 측정 가능량을 나타내는 세가지 연산자를 통하여 고전 이론과는 달리 양자 이론에서는 빛살 가르개를 통과한 후 빛의 세기와 위상에 대한 불확실도가 증가함을 보이고 이를 진공 요동에 의한 효과로 정량적으로 분석하였다. 한편 진공효과를 배제하는 과정으로서 정규 차례를 따르는 연산자에 대한 기대치는 고전적 파동 이론의 결과와 일치함을 보임으로써 고전적 파동 이론과의 대응성을 추구하였다. 또한 이러한 결과로부터 진공 효과를 포함하는 실제의 측정 위상과 고전 이론에 대응하는 추측 위상의 구분 및 그 관계를 보였다.

• 국제학술발표논문집
• /
• The 6th International Conference on Construction Engineering and Project Management
• /
• pp.738-739
• /
• 2015

The main objective of this study, "Spatial Downscaling of Precipitation from GCMs for Assessing Climate Change over Han River and Imjin River Watersheds", is to carry out over Han River and Imjin River watersheds. To this end, a statistical regression method with MOS (Model Output Statistics) corrections at every downscaling step was developed and applied for downscaling the spatially-coarse Global Climate Model Projections (GCMPs) from CCSM3 and CSIRO with respect to precipitation into 0.1 degree (about 11 km) spatial grid over study regions. The spatially archived hydro-climate data sets such as Willmott, GsMap and APHRODITE datasets were used for MOS corrections by means of monthly climatology between observations and downscaled values. Precipitation values downscaled in this study were validated against ground observations and then future climate simulation results on precipitation were evaluated for the projections.

• 디자인학연구
• /
• 제16권3호
• /
• pp.299-308
• /
• 2003

21세기 지식정보화 시대를 살고있는 지금 Digital 시대가 심화되어감에 따라 기존 시장형태와 사회구조에 큰 변화가 가시화되고 있다. 소비시장의 특징은 힘의 균형이 기업에서 소비자로의 이동이다. 생활수준의 향상에 따른 소비자의 욕구가 다양해지면서 인간의 경험과 감성, 가치에 기반을 둔 다양한 상품들이 히트상품의 양 축을 이루고 있다. 상품의 규격화된 기능과 서비스로는 더 이상 소비자를 사로잡기 어렵다. 소비자가 원하는 것은 감동적인 경험을 제공하는 상품이나 서비스라는 사실에 주목해야 한다. 미래의 상품은 이성이 아니라 소비자의 감성에 호소해야한다. 이제 소비자는 상품자체가 아니라 상품에 담겨있는 스타일과 경험과 이야기를 구매한다. 즉 구매결정의 관건은 감성 가치의 만족인 것이다. 산업디자인의 발전으로 다양해진 사용자의 감성은 사용자들의 새로운 취향을 대변해줄 수 있는 새로운 디자인의 개발이 요구되어지고있다. 사용자중심의 가치관으로의 전환은 자동차에 대한 의식의 변화로 가격, 기능의 물리적 관점에서 개인지 감성과 개성중심으로 변화하여 기능적 형태의 디자인에서 새로운 감성가치를 추구하는 디자인 개념으로 연구되어야한다. 변화의 시대를 맞이하여 디자이너가 주체적이고 합리적인 변화의 방향을 제시해야 할 시점이다.

• The Journal of Advanced Prosthodontics
• /
• 제11권4호
• /
• pp.215-222
• /
• 2019

PURPOSE. To evaluate the polishing effect on roughness and color change of pressed and layering ceramics after immersion in coffee solution. MATERIALS AND METHODS. 88 ceramic discs ($1.0mm{\times}10.0mm$) were manufactured - 44 nano-fluorapatite layering ceramics (IPS e.max Ceram. Group C) and 44 pressed lithium disilicate ceramic discs (IPS e. max Press - Group P). Each group was divided into 4 subgroups according to surface treatments: (G) Glaze, (S) Shofu polishing system (Shofu Inc.), (E) Edenta AG polishing System, (KG) $30-{\mu}m$ diamond granulation tip. Surface roughness (Ra) and color change (${\Delta}E$) measurings after the surface treatments were performed, before and 12 days after the immersion in coffee solution. A samples' qualitative analysis was conducted with a scanning electron microscopy (SEM). Data were statistically-treated with one-way-ANOVA and Duncan's tests, apart from paired t-test and Pearson's correlation test (${\alpha}=5%$). RESULTS. The decrescent order, both for surface roughness (Ra) and ${\Delta}E$ for both ceramics were: KG > E > S > G (P<.05). With exception for PG and CG subgroups, which did not present statistical difference between them, all other pressed ceramics subgroups presented smaller Ra values and greater ${\Delta}E$ values than the layering ceramics subgroups (P<.05). CONCLUSION. Although mechanical polishing systems presented intermediate Ra values, their colors were considered clinically acceptable. There is a strong correlation between the surface roughness and the color change of tested ceramics.

• Journal of Oral Medicine and Pain
• /
• 제48권4호
• /
• pp.152-158
• /
• 2023

Purpose: This pilot study aimed to evaluate changes in joint space (JS) using cone-beam computed tomography (CBCT) images of patients diagnosed with temporomandibular joint (TMJ) osteoarthritis (OA) and to determine the association between occlusal changes and JS. Methods: CBCT images were used to measure the anterior, superior, and posterior JSs of the sagittal plane. The differences in JS values over time and between groups were compared. The percentage change in the anteroposterior position of the mandibular condyle between groups was also analyzed. Results: Thirty-four subjects (mean age=43.91±20.13), comprising eight males (23.5%) and 26 females (76.5%), were divided into 18 patients with no change in occlusion (NCO) and 16 patients with a change in occlusion (CO) during TMJ OA. The JS measurements of the study subjects showed a decrease in anterior joint space (AJS) values over time. There was no difference in JS measurements between the groups at T1 and T2. AJS values measured at T1 were lower in the CO group than in the NCO group, but the difference was not statistically significant. In both groups, a posterior position of the mandibular condyle was initially observed with high frequency. However, there is a statistically significant difference in CBCT images taken after occlusal changes, with an increased frequency of condyles observed in the anterior or central positions. Conclusions: In conclusion, AJS decreased over time in TMJ OA, and the mandibular condyle became more anteriorly positioned with occlusal changes. Therefore, clinicians should diligently monitor mandibular condyle morphology and JS using CBCT, along with the patient's clinical symptoms, to treat and control TMJ OA effectively.

• 대기
• /
• 제17권1호
• /
• pp.17-26
• /
• 2007

The station relocations, the replacement of instruments, and the change of a procedure for calculating derived climatic quantities from observations are well-known nonclimatic factors that seriously contaminate the worthwhile results in climate study. Prior to embarking on the climatological analysis, therefore, the quality and homogeneity of the utilized data sets should be properly evaluated with metadata. According to the metadata of the Korea Meteorological Administration (KMA), there have been plenty of changes in the procedure computing the daily mean values of temperature, humidity, etc, since 1904. For routine climatological work, it is customary to compute approximate daily mean values for individual days from values observed at fixed hours. In the KMA, fixed hours were totally 5 times changed: at four-hourly, four-hourly interval with additional 12 hour, eight-hourly, six-hourly, three-hourly intervals. In this paper, the homogeneity in the daily mean temperature dataset of the KMA was assessed with the consistency and efficiency of point estimators. We used the daily mean calculated from the 24 hourly readings as a potential true value. Approximate daily means computed from temperatures observed at different fixed hours have statistically different properties. So this inhomogeneity in KMA climate data should be kept in mind if you want to analysis secular aspects of Korea climate using this data set.