• Korean Journal of Metals and Materials
• /
• v.46 no.12
• /
• pp.800-808
• /
• 2008

Heat treatment is an important step for tool manufacture, but unavoidably generates dimensional distortion. This study investigated the continuous dimensional change and the anisotropic behavior of STD11 tool steel during austenitizing and tempering heat treatment especially using quenching dilatometer. Dilatometric results represented that the dimensional change along longitudinal direction was larger than that along transverse direction. Anisotropic phase transformation strain was produced in forged STD11 tool steel during heat treatment. Anisotropic dimensional change increased with increasing austenitizing temperature. After tempering, anisotropic distortion was partially reduced. FactSage thermodynamic equilibrium phase simulation and microstructural observation (FE-SEM, TEM) showed that large ($7{\sim}80{\mu}m$) elongated $M_7C_3$ carbides could be formed along rolling direction. The resolution of elongated carbides during austenitizing was found to be related with the change of martensite transformation temperature after heat treatment. Anisotropic size change of STD11 tool steel was mainly attributed to large elongated carbides produced during rolling process. Using dilatometric and metallographic examination, the possible mechanism of the anisotropic size change was also discussed.

• Journal of Software Assessment and Valuation
• /
• v.16 no.2
• /
• pp.143-151
• /
• 2020

The digital content's security and authentication are important in the field of digital content application. There are some methods to perform the authentication. The digital watermarking is one of authentication methods. Paper presents a digital watermark authentication method that works in the application of digital image. The proposed watermark has the triple status information and performs the embedding and the detection without original Content. When authenticating the owner information of digital content, an autocorrelation function is used. In addition, a spread spectrum method is used to be adaptive to the signal of the original content in the frequency domain(DWT Domain). Therefore, the possibility of errors occurring in the detection of hidden information was reduced. it also has a advantage what Watermarking in DWT has faster embedding and detection time than other transformation domains(DFT, DCT, etc.). if it has a an image of size N=mXm, the computational amount can be reduced from O(N·logN) to O(N). The particular advantage is that it can hide more information(bits) per bit.

• Journal of Environmental Impact Assessment
• /
• v.33 no.1
• /
• pp.30-41
• /
• 2024

The way we work is changing significantly with the rapid development of digitaltechnology, and paper documents are being replaced by electronic documents. However, in accordance with the Enforcement Decree and Enforcement Regulation of the Environmental Impact Assessment Act, the environmental impact assessment report must submit a set number of paper reports to organizations related to the project, and about 42 years have passed since it was submitted as a paperreport. In 2022, the National Institute of Ecology introduced a system to review paperreports as electronic documents in line with the trend of digital transformation. The cost reduction and carbon emission reduction effects of electronic document review were analyzed for 1,398 environmental impact assessments submitted and reviewed in 2022. In addition, a satisfaction survey was conducted targeting type 1 environmental impact assessment companies that were directly affected, and a total of 134 people responded. As a result of analyzing the effect of reviewing electronic documents, costs are reduced by a total of 101,424,900 won per year and carbon emissions are reduced by about 59.7 tons. As a result of the satisfaction survey, 94.8% of the respondents said electronic documentreview was very helpful, and 4.5% said it was helpful. The effectiveness of electronic documentreview was high, with 94.8% of respondents saying it was helpful in economic terms and 91.8% saying it was helpful in reducing work hours. If electronic documents are reviewed through the revisions to the Enforcement Decree and Enforcement Regulation of the Environmental Impact Assessment Act, the implementation of electronic document review is expected to have a ripple effect across the country, not only reducing costs and carbon emissions, but also reducing administrative time and saving storage space. Rapid changes in law and administration are needed to adapt to the digital transformation era.

• Journal of the Korean Geographical Society
• /
• v.40 no.1 s.106
• /
• pp.27-46
• /
• 2005

Land suitability assessment(LSA) is a useful method to assess land characteristics according to its physical, locational, and environmental characteristics, and then to classify it into several categories based on its usability and the necessity for conservation. Therefore, the credibility of this assessment result depends on the rationality of assessment method such as computation of suitability values and the criteria of ranking the land grade. This study focused on identifying problems in current LSA method by critically reviewing it, and aimed to suggest a suitable method for the assessment of land suitability. As a alternative method in this study, linear transformation method was used for scoring factors instead of critical values and the weight for each assessment factor. and all values of those factors were added to produce comprehensive suitability values. Those values were ordered and categorizied with suitability level based on the ratio of square measure. After comparing existing LSA method to the suggested alternative method, it is concluded that the alternative method was more suitable to assess the characteristics of lands than existing LSA method. This method was also suitable to represent the characteristics of various assessment factors. Field survey using satellite image clearly revealed the suitability of the alternative method compared to an existing method of land assessment. Furthermore, the alternative method of grading the land suitability improves the problem of using standardiZiation method and gives more flexibility, which makes this method very rational.

• Journal of Korea Water Resources Association
• /
• v.36 no.3 s.134
• /
• pp.399-411
• /
• 2003

An approach determining a confidence interval of Nash's observed mean instantaneous unit hydrograph is developed. In the approach, both two parameters are treated as correlated gaussian random variables based on the theory of Box-Cox transformation and the regional similarity relation, so that linear statistical parameter estimation is possible. A parametric bootstrap method is adopted to give the confidence interval of the mean observed hydrograph. The proposed methodology is also applicable to estimate the parameters of Nash's model for un-gauged basins. An application to a watershed has shown that the proposed approach is adequate to assess the uncertainty of the Nash's hydrograph and to evaluate parameters for un-gauged basins.

• Proceedings of the KSRS Conference
• /
• v.2
• /
• pp.555-558
• /
• 2006

In recent years, urban development has expanded rapidly in Nawabshah City of Pakistan. A major effect associated with this population trend is transformation of the landscape from natural cover types to increasingly impervious urban land. The core objective of this study are to provide time-series information to define and measure the urban land cover changes of Nawabshah, Pakistan between the years 1992 and 2002, and to examine related urbanization impacts on air quality of the study area. Two multi-temporal Landsat images acquired in 1992 and 2002 together with standard topographical maps to measure land cover changes were used in this study. The image processing and data manipulation were conducted using algorithms supplied with the ERDAS Imagine software. An unsupervised classification approach, which uses a minimum spectral distance to assign pixels to clusters, was used with the overall accuracy ranging from 84 percent to 92 percent. Land cover statistics demonstrate that during the study period (1992-2002) extensive transformation of barren and vegetated lands into urban land have taken place in Nawabshah City. Results revealed that land cover changes due to urbanization has not only contaminated the air quality of the study area but also raised the health concerns for the local residents.

• Journal of the Korean Society for Heat Treatment
• /
• v.24 no.5
• /
• pp.262-270
• /
• 2011

Carbide precipitation and dissolution behavior at various temperatures during heat treatment has been studied in STD11 cold working die steel through confocal scanning laser microscopy; dilatometry; and X-ray diffraction analysis. The equilibrium phase diagram and phase fractions with temperature were calculated using a FactSage program. Confocal laser microscopic observation revealed that ${\alpha}$ to ${\gamma}$ transformation temperature is near $800^{\circ}C$; M7C3 carbides melt at $1245^{\circ}C$; and the melting temperature of STD11 is near $1370^{\circ}C$. XRD results indicated that the M23C6 carbides dissolve in the matrix if austenitized at over $1030^{\circ}C$; while the M7C3 carbides remain up to $1200^{\circ}C$ although their amount decreases. The calculated equilibrium phase diagram showed good agreement with experimental results on carbide dissolution and phase transformation temperatures.

• Korean Journal of Remote Sensing
• /
• v.36 no.1
• /
• pp.15-27
• /
• 2020

Accurate knowledge of land use/land cover (LULC) features and their relative changes over upon the time are essential for sustainable urban management. Urban sprawl growth has been always also a worldwide concern that needs to carefully monitor particularly in a developing country where unplanned building constriction has been expanding at a high rate. Recently, remotely sensed imageries with a very high spatial/spectral resolution and state of the art machine learning approaches sent the urban classification and growth monitoring to a higher level. In this research, we classified the Quickbird satellite imagery by object-based image analysis of Dempster-Shafer (OBIA-DS) for the years of 2002 and 2015 at Karbala-Iraq. The real LULC changes including, residential sprawl expansion, amongst these years, were identified via change detection procedure. In accordance with extracted features of LULC and detected trend of urban pattern, the future LULC dynamic was simulated by using land transformation model (LTM) in geospatial information system (GIS) platform. Both classification and prediction stages were successfully validated using ground control points (GCPs) through accuracy assessment metric of Kappa coefficient that indicated 0.87 and 0.91 for 2002 and 2015 classification as well as 0.79 for prediction part. Detail results revealed a substantial growth in building over fifteen years that mostly replaced by agriculture and orchard field. The prediction scenario of LULC sprawl development for 2030 revealed a substantial decline in green and agriculture land as well as an extensive increment in build-up area especially at the countryside of the city without following the residential pattern standard. The proposed method helps urban decision-makers to identify the detail temporal-spatial growth pattern of highly populated cities like Karbala. Additionally, the results of this study can be considered as a probable future map in order to design enough future social services and amenities for the local inhabitants.

• Toxicological Research
• /
• v.30 no.4
• /
• pp.261-266
• /
• 2014

Environmental pollutants such as polycyclic aromatic hydrocarbons (PAHs) have been implicated in cancer development and progression. However, the effects of PAHs on carcinogenesis are still poorly understood. Here, we characterized a mouse cancer cell line BNL 1ME A. 7R.1 (1MEA) derived by transformation of non-tumorigenic liver cell line BNL CL.2 (BNL) using 3-methylcholanthrene (3MC), a carcinogenic PAH. RT-PCR and immunoblot analysis were used to determine the expression level of mRNA and proteins, respectively. To determine functionality, cell motility was assessed in vitro using a transwell migration assay. Both mRNA and protein levels of E-cadherin were significantly decreased in 1MEA cells in comparison with BNL cells. While the expression levels of mesenchymal markers and related transcription factors were enhanced in 1MEA cells, which could lead to increase in cell motility. Indeed, we found that 7-day exposure of BNL cells to 3-MC reduced the level of the adhesion molecule and epithelial marker E-cadherin and increased reciprocally the level of the mesenchymal marker vimentin in a dose-dependent manner. Taken together, these results indicate that the process of epithelial-mesenchymal transition (EMT) may be activated during premalignant transformation induced by 3-MC. A mechanism study to elucidate the relation between 3-MC exposure and EMT is underway in our laboratory.

• Environmental Analysis Health and Toxicology
• /
• v.13 no.1_2
• /
• pp.43-53
• /
• 1998

Ambient air levels of polycyclic aromatic hydrocarbons(PAHs) are of concern because of their potential for adverse health effects including transformation of some of these substances to mutagens and carcinogens by mammalian microsomal enzyme system. Airbone particulate samples were collected by a conventional high-volume sampler and by an Anderson cascade impactor on 2 to 3 days in each month over a period of 1 year at a representative site of the heavy traffic area of Seoul from beptember 1994 to August 1995. Ten individual PAHs in sizable air particulates of each stage of two months were separated and analyzed by gas chromatography/mass spectrometry. As a results of analysis, the gross concentrations of PAHs in the fine and coarse particles were higher in the winter month than in the spring, followed in descending order by in the fall and summer. In a study of dependency of 10 PAHs compounds on size distribution of particles at heavy traffic area found that about 85% of the total PAHs content was associated with particles less than 2.0um (fine particles) in diameter of winter sampling period. while 79% were associated with this size fraction during summer period. In according to the mean concentrations of the 10 PAHs in 7 size classification from < 0.38 to> 10.1, the 'size was the smaller, PAHs concentration was the higher. Thus it was found that PAHs concentration was greatly affected by air particle size. Annual mean benzo(a)pyrene equivalents was 5.88ng/m$^3$ and obtained by applying, toxic equivalency factor developed by Nisbet and Lagoy.