• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.4
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• pp.383-395
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• 2008

The grouting is one of the improved techniques which is aim to decrease the permeability and to strengthen the soft ground. But The grouting method has many problems about a suitability of grouting procedure and an effectiveness of grouting after grouting work because of a technical characteristic operated inside the soil. The grouting $p{\sim}q{\sim}t$ chart of a typical index about grouting rate and time alteration of grouting pressure is one method to estimate the suitability of grouting factor with monitoring during grouting procedure. This study is automatic grouting system (AGS) which can control the testing and grouting procedures. It can make the detailed $p{\sim}q{\sim}t$ chart and analyze the grouting characters of the ground by comparing the detailed pattern of $p{\sim}q{\sim}t$ chart with standard pattern. If using the $p{\sim}q{\sim}t$ chart derived from AGS in the grouting work, it is an objective standard estimating the suitability of grouting factor with grouting materials, grouting method, grouting rate and grouting pressure, as results it expects successfully to improve reliability of the grouting work.

• Polymer(Korea)
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• v.36 no.6
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• pp.712-720
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• 2012

Thermal degradation for glass fiber-reinforced polyamide 66 composite (PA 66) with respect of thermal exposure time has been investigated using optical microscopy, scanning electron microscopy and Fourier transform infrared spectroscopy. As the thermal exposure time was prolonged, a slight increase in tensile strength for only initial stage and afterward, a proportional decrease of tensile strength was observed. These results can be explained by the increase of crystallinity, followed by the increase of crosslinking density, chain scission and the decrease in chain mobility, due to thermal oxidation with the exposure time. Fourier transform infrared spectroscopy results showed the increase of ketone peak and silica peak on the surface of thermally exposed PA 66. In addition, the thermal decomposition kinetics of PA 66 was analyzed using thermogravimetric analysis at three different heating rates. The relationship between activation energy and lifetime-prediction of PA 66 was investigated by several methodologies, such as statistical tool, UL 746B, Ozawa and Kissinger. The activation energy determined by thermogravimetric analysis had a relatively large value compared with that from the accelerated test. This may result in over-estimating the lifetime of PA 66. In this study, a master curve of exponential fitting has been developed to extrapolate the activation energy at various service temperatures.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.366-376
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• 2017

This study attempts to analyze the structure of the knowledge and duties of the vocational counseling service industry by using the text mining method and network analysis, which are methods of big data analysis. The subjects of the survey were vocational counseling, job placement and career change support, three fields in the unit elements of competence included in the National Competency Standards (NCS) which areproposed by the government. Although the analysis results of frequently used words showed that all three fields had independent duties, many were overlapping, such as counseling, examination, employment support, etc. for clients, job seekers, and others. The knowledge required by the employees of this field includes many new fields, such as start-up development, lifelong career consulting, job adaptation and culture conflict, besides the five subjects of vocational psychology, vocational counseling, labor market, job information, and law, which are included in the vocational counselor certification examination. Also, we suggested that the consultants adhere to emotional approaches, such as empathy, acceptance and attentiveness, and take a neutral stance. This study isvaluable in that it is the first attempt to objectively analyze the duties of the vocational counseling service field by big data analysis. In addition, it is also meaningful that we first confirmed the difference between the direction of government policy and the actual practice in the field.

• Economic and Environmental Geology
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• v.45 no.2
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• pp.169-180
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• 2012

The ESBs (Environmental Specimen Banks) have monitoring functions for the contemporary environmental qualities and also offer the future generation tangible information on the past environment by preserving the specimens. This entails the sampling of the representative specimen for each distinctive ecosystem, which is performed under a strict and stipulated procedure and a condition that does not allow any change in the component so that a retrospective analysis can be readily done even in the distant future. It has been more than 30 years that some developing countries started collecting a broad spectrum of specimens to vindicate the effectiveness of an environmental policy and to monitor the long-term variations of background concentrations of environmental pollutants. Though being late, the National Institute of Environmental Research (NIER), Korea, has successfully launched the National Environmental Specimen Bank (NESB) in 2009 equipped with its state-of-the-art automated cryogenic tanks. Since then, the researchers at the NESB have been doing their best to excel the existing ESBs around the world by learning and improving the expertise. To do so, they conducted a pilot study for developing and testing their own Standard Operating Procedure (SOP) based on the analysis of the examples of the other ESBs. The problems from the pilot study had been reviewed to improve the SOP to meet the requirements for an ESB, that is to say, preserving representative environmental specimens in cryogenic condition and enhancing the analytical method. Furthermore, they also need to prepare themselves to address the future challenges by providing some additional functions, which makes it distinguishable from the other ESBs. If successful, this will be a step further to be recognized as a full-fledged member of the ESB society of the world.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.3
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• pp.195-202
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• 2007

The normalized difference in incident solar energy between a target surface and a level surface (overheating index, OHI) is useful in eliminating estimation error of site-specific maximum temperature in complex terrain. Due to the complexity in its calculation, however, an empirical proxy variable called northern exposure index (NEI) which combines slope and aspect has been used to estimate OHI based on empirical relationships between the two. An experiment with real-world landscape and temperature data was carried out to evaluate performance of the NEI - derived OHI (N-OHI) in reduction of spatial interpolation error for daily maximum temperature compared with that by the original OHI. We collected daily maximum temperature data from 7 sites in a mountainous watershed with a $149 km^2$ area and a 795m elevation range ($651{\sim}1,445m$) in Pyongchang, Kangwon province. Northern exposure index was calculated for the entire 166,050 grid cells constituting the watershed based on a 30-m digital elevation model. Daily OHI was calculated for the same watershed ana regressed to the variation of NEI. The regression equations were used to estimate N-OHI for 15th of each month. Deviations in daily maximum temperature at 7 sites from those measured at the nearby synoptic station were calculated from June 2006 to February 2007 and regressed to the N-OHI. The same procedure was repeated with the original OHI values. The ratio sum of square errors contributable by the N-OHI were 0.46 (winter), 0.24 (fall), and 0.01 (summer), while those by the original OHI were 0.52, 0.37 and 0.15, respectively.

• The Transactions of the Korea Information Processing Society
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• v.3 no.2
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• pp.283-294
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• 1996

To operate the automatic devices of manufacturing process more effectively and to solve the needs of the resource sharing, network technology is applied to the unit control devices located in common manufacturing zone and operated by connecting them. This paper introduces deign and test operation of cell system for the management of multivendor PLC by applying to wall paper process based on the manufacturing standardization of CIM. The analysis of designed multivendor PLC group is performed by selecting the parameters such as variation of data packet size and node number of PLC ladder logic program and variation by analyzing the corresponding variation values of token rotation time and waiting time for the system operation. For the method of the analysis,the equation is considering the overhead such as indicated packet service time and transmission safety margin for PLC network connection in M/G/1 queue model,and it is applied to the cell system and PLC group manage-ment for operation .Through the experiment,it is found that the realtime processing is possible with expanded and better result than the resuit obtained by Jayasumana.Browaka with PLC scan time considered,response lower limit of 10-20 msec. data packet size not more than 50 bytes.and the number of nodes less than 40.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.3
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• pp.265-269
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• 2009

Technology development for sufficient dry matter production of Chinese milk vetch (CMV) is most important in CMV-rice cultivation system in order to provide sufficient nutrients to rice plants. However, when the CMV plants are dominated by the weed, especially Alopecurus aequalis, the CMV growth could be reduced due to light and nutrient competition. In addition, A. aequalis is potential host of the rice dwarf virus disease. Therefore, control of A. aequalis is necessary to enhance the biomass production of CMV plants when CMV stands are insufficient. The use of chemical like sethoxydim (20%, ai) showed the highest control rate of 84% at early stage and was reduced as application was delayed. A. aequalis control did not change the CMV seedling stand before and after herbicide treatment and the reseeding stand in fall was rather increased 2.2 to 2.6 times. On the other hand, in untreated control, the CMV stand at May 15 and reseeding stand in fall was significantly reduced as compared with the before herbicide treatment. Control of A. aequalis increased the CMV dry matter production by 164% for 50% CMV coverage rate and 63% for 25% CMV coverage rate. This is equivalent to $12.3{\sim}16.4\;kgN$/10a which is greater than the recommended nitrogen rate of 9kg/10a. The result indicates that the control of A. aequalis is an efficient way to enhance dry matter production in CMV-rice cultivation system especially when CMV stand is poor.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.5
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• pp.412-423
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• 2000

By using the relation between stress intensity factor and AE parameter, new approach method for assessing the crack length and detectability of crack was proposed. Laboratory experiment was carried out to identify AE characteristics of fatigue cracks for compact tension specimen. The relationship between a stress intensity factor and AE signals activity as well as conventional AE parameter analysis was discussed. As a result, the features of specific parameter such as the length of crack growth the AE energy, the AE peak amplitude, and the cumulative AE hits, showed the almost same trend in their increase as the number of fatigue cycle increased. From the comparisons of peak amplitude and AE energy with stress intensity factor, it was verified that the higher stress intensity factors generated AE signals with higher peak amplitude and a larger number of AE counts. If we can get more reliable database for the relation between AE parameters and stress intensity factor, this approach will provide a good information for evaluating both the existence of crack and the minimum detectable size of crack.

• Applied Biological Chemistry
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• v.13 no.1
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• pp.73-79
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• 1970

The present study has been undertaken to see if any proper measure be found for the determination of available phosphorus by chemical extraction on the basis of A-values as the standard. The results obtained are described as follows. 1. Since A-value of the samples under study showed a significant correlation with Fe-P at 1% level. The available phosphorus in the present paddy soils was considered to be affected by Fe-P. 2. Six methods for chemical extraction were not correlated with the determination of Fe-P, proving them inadequate for the quantitative measurement of available phosphorus. 3. Adequate method for extracting available phosphorus in paddy soils should rest on the measurement of the reduction intensity of Fe-P. The extractable intensity was estimated to be 270 ppm in average. 4. Bray No. 2-P showed significant correlation with Lancaster-P, Spurway-P, Truog-P, and (Ca+Al)-P at 5% level. Olsen-P and Lancaster-P indicated significant correlation with Al-P and Spurway-P with Ca-P respectively at 1% level.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.6
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• pp.188-197
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• 2010

This paper presents research result to study the change of structural capacity of reinforced concrete beams with various shear reinforcement ratios after damage by fire load. In addition, fundamental data are given in order to predict the strength variation of RC member due to fire damage by evaluating the previous calculation method codified in codes. Nine RC beam specimens were made and exposed to the fire controled by the standard fire curve. And the structural capacity was evaluated through a failure test under simple support condition. Previous code formula, ACI code and Eurocode were reviewed and used for the calculation of the strength of specimens damaged by fire. From the test, RC beam specimens exhibited very brittle failure when it exposed to fire controled by standard fire curve during more than one hour. And this failure pattern tended to be more serious when shear reinforcement ratio decreased or fire loading duration increased. From the evaluation of the calculation process in code, the change of strength due to fire can be properly predicted if the damage of materials is well defined.