• Journal of the Korean GEO-environmental Society
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• v.16 no.8
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• pp.13-20
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• 2015

Due to the population growth and exhaustion of resource, the development on the harsh environment such as cold weather is emerging as an alternative for new resource development. The permafrost area covers about 14 percent of the world's land area and the global construction market for such area is rapidly expanded. Whereas the developed countries have already recognition of the need for research of coldest place and invested heavily in technology development, the domestic technology for the coldest place development is less developed and related research has rarely been performed. There is not a detailed national specification standard for the strength and deformation properties of the earthworks at sub-zero temperature but simple field directions. Therefore, the D compaction tests were conducted on the sand with fine contents of 0%, 5%, 10% and 15% at room temperature ($18^{\circ}C$), $-3^{\circ}C$ and $-8^{\circ}C$ to investigate the effect of the compaction energy on the compacted soils at sub-zero temperatures. Based on the test results, the larger compaction energy, the larger maximum dry unit weight under sub-zero temperature and D type compaction at $-3^{\circ}C$ show similar max. dry unit weights as those obtained from the compaction at the room temperature. However, compaction at $-8^{\circ}C$ showed significant performance degradation regardless of the compaction energy.

• Korean Journal of Construction Engineering and Management
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• v.11 no.1
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• pp.88-100
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• 2010

As the competition between companies are deepened, the number of companies adopting six sigma principles, which is one of the innovative management strategies, are increasing. According to this trend, the changes in both strategies and methodologies of six sigma are continuous. However, the evaluations and the management principles included in the process after the six sigma applications are insufficient, and the cooperation between the parties in the company is also not enough because the application process of six sigma is too complex and not efficient. In order to solve this problem, a research for developing the methodology which can learn about and do six sigma applications is so necessary, specifically for expanding the six sigma applications and introducing the participation of all company members. The purpose of this study, therefore, was to develop and present more efficient Six Sigma applied process by reducing the existing unnecessary steps in improvement one, by applying the examination method of wasteful elements on the potential factors, through analyzing the Six Sigma DMAIC applied case in the construction industry. The result of those application showed that the detection of potential factors using wasting elements was possible in measurement step and that it was possible for the improved process with reduced steps compared to existing process while to remain the outcomes. It is considered that the performance rate of Six Sigma project will be improved significantly because the reduction in the improvement step does not affect the improvement effect within the whole Six Sigma project.

• Journal of Pharmacopuncture
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• v.19 no.3
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• pp.207-212
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• 2016

Objectives: Acupuncture treatments are safe and effective for a wide variety of diseases involving autonomic dysregulation. Heart rate variability (HRV) is a noninvasive method for assessing sympathovagal balance. The low frequency/high frequency (LF/HF) spectral power ratio is an index of sympathovagal influence on heart rate and of cardiovascular health. This study tests the hypothesis that from rest to 30% to 50% of peak oxygen consumption, the nonlinear Conte-Zbilut-Federici (CZF) method of computing the LF/HF ratio is a more reliable index of changes in the HRV than linear methods are. Methods: The subjects of this study were 10 healthy young adults. Electrocardiogram RR intervals were measured during 6-minute periods of rest and aerobic exercise on a cycle ergometer at 30% and 50% of peak oxygen consumption ($VO_{2peak}$). Results: The frequency domain CZF computations of the LF/HF ratio and the time domain computations of the standard deviation of normal-to-normal intervals (SDNN) decreased sequentially from rest to 30% $VO_{2peak}$ (P < 0.001) to 50% $VO_{2peak}$ (P < 0.05). The SDNN and the CZF computations of the LF/HF ratio were positively correlated (Pearson's r = 0.75, P < 0.001). fast Fourier transform (FFT), autoregressive (AR) and Lomb periodogram computations of the LF/HF ratio increased only from rest to 50% $VO_{2peak}$. Conclusion: Computations of the LF/HF ratio by using the nonlinear CZF method appear to be more sensitive to changes in physical activity than computations of the LF/HF ratio by using linear methods. Future studies should determine whether the CZF computation of the LF/HF ratio improves evaluations of pharmacopuncture and other treatment modalities.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.11
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• pp.2621-2627
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• 2014

Directional transmission is one of key technology to solve the utmost problem that current mobile communication system faces, which is explosively increasing data traffic, since directional transmission can maximize the throughput of mobile communication systems. In this work, we consider power allocation scheme for mobile communication system which utilizing directional transmission. Especially, we consider the case in which multiple users in the same sector of base station, are served at the same time by utilizing directional transmission. For this scenarios, we consider equal power allocation scheme, Water-filling based scheme and inverse SNR scheme. Moreover, we propose beam power allocation scheme whose objective is to maximize overall system throughput by taking into account interference between different directional transmissions. Moreover, we have examined the spectral efficiency and Jain's fairness index of various power allocation schemes for directional transmission by using system level simulator that has been developed in our previous work. Through simulations, it has been verified that the proposed power allocation scheme can improve the spectral efficiency of the system by 28%.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.3
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• pp.288-294
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• 2005

This study was conducted to evaluate the grit removal efficiency of tornado block-type vortex grit separator. Vortex grit separator was manufactured for this study, and it was characterized by the impeller and tornado block installed in separator. Impeller was installed to increase water velocity in the separator and tornado block was installed to increase the grit lifting efficiency. Pilot study was also conducted in A sewage treatment plant (STP) in Gyeonggi province from November 2003 to May 2004 (64 days). Major findings are as follows. 1. Impeller was proven to increase water velocity in the grit separator, especially in low flow rate. This influence will increase separation ratio of organics from grits, preventing those organics from sedimentation. 2. Sand (with 0.2~0.3mm size) removal efficiency was over 98 % and 96 %, at the flow rate of $500m^3/day$ and $750m^3/day$ under the condition that impeller rotation velocity kept at 15 rpm. Originally that grit separator was designed to have the capacity of $500m^3/day$. $750m^3/day$ was tried to investigate the performance of this type of grit separator under overload condition. Stable grit removal was still available to the extent of 150% of designed capacity. 3. It took less than 3 minutes for the grit separator to completely lift out 3 kgs of 0.2-0.3 mm sized, settled sand at the bottom to 2,060 mm high above water surface. But it showed the tendency to spend a little more time on lifting the grit as the grit size and the vertical height of the lift increased. 4. During experimental duration in A STP, it was found that the average amount of inlet grit was about 981 g/day (160~1,685 g/day) under $500m^3/day$ of operation condition, but it varied so severely during the experimental duration. After classification of discharged grit according to its size, grit with 0.3-0.42 mm size was found as largest part of output.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.655-665
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• 2016

Considering the importance of SMEs, which account for 88% of employment and 99% of domestic businesses, the government has implemented informatization policy support. On the other hand, due to budget limitations and the ability of the private market, it is time to transition to the new policy of the informatization support paradigm. This study evaluated the informatization policy support of SMBA by a comparison with the stage model to determine the future direction. The informatization development model is a step model divided into five levels ranging from the informatization initiation level to the strategic innovation level. The informatization policy of SMBA was focused on the development of automation and in-house integration, and business-to-business integration and strategic innovation step was found to be lacking. Based on these results, there are three implications for the informatization policy of the next SMEs. First, there is a need for a movement of the center of the support in the informatization step to the strategic innovative step. Second, by establishing an informatization road map, it is necessary to develop their own informatization capabilities according to the road map. Finally, it is important to improve the effectiveness of informatization support based on performance rather than policy providers.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.3
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• pp.161-172
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• 2013

Metadata registry (MDR) is the international standard, developed by ISO/IEC for exchange and sharing data between databases. Many MDR systems are used in diverse domains such as medical service, bibliography, environment for sharing and integrating data. However, those systems have different physical structures individually because the MDR standard defines only the metamodel for registering and storing metadata. It causes heterogeneity between the system structures and requires additional cost to maintain interoperability. ISO/IEC 13249-8 Metadata Registry Access (MRA) is developing as an international standard to provide a consistent access facility to data stored in different metadata registries. However, MRA does not consider the relationships between the concepts (classes) defined in the MDR specification. It causes that incorrect query results returned from MDR systems. It also requires additional cost of modeling and rewriting queries to reflect each physical model. Therefore, this paper suggests eMRA which considers the relationships between the concepts in MDR. The comparative evaluations are described to show the advantages of eMRA. eMRA has superior performance in query modeling and referential integrity than MRA defined by the relationship between the concept of MDR.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.545-552
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• 2021

In this study, strength and durability evaluations are performed on vibrated-rolled method mortar mixtures containing desulfurized gypsum and ferronickel slag powder. Desulfurized gypsum and ferronickel slag fine powders were substituted for 25% limestone fine powders u sed in the manu factu re of VR tu bes, and mortar specimens were prepared u sing vibrated-rolled method. Accordingly, flexural and compressive strengths were performed to evaluate the strength, and chlorine ion penetration resistance and sulfuric acid resistance tests were performed to evaluate durability. Flexural and compressive strength were improved in the range 20 to 60% of desu lfu rized gypsu m among admixtu res, and the amou nt of passing charge decreased in the choride ion penetration resistance test in the range of 20 to 80% of desulfurized gypsum. As for the resistance to su lfu ric acid, when the proportion of desu lfu rized in the admixtu re was 40%, the strength and weight change rate according to the immersion period was reduced. Appropriate use of desulfurized gypsum and ferronickel slag powder is expected to improve performance in terms of strength and durability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.293-302
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• 2019

This study systematically analyzed computer-based driving intervention programs for seniors, to provide the academic background for driving intervention for seniors. Articles published from January 2009 till December 2018 were researched and analyzed. 'PubMed, Google Scholar, and Science Direct' were used to search articles published overseas, and 'RISS, KERIS, and KISS' searched for articles published in Korea. Based on the inclusion and exclusion criteria, totally 359 papers were retrieved, and 10 articles were finally analyzed; 8 articles (80%) were evidence level I, and 2 articles (20%) were evidence level III. Amongst the computer-based interventions, driving simulators (70%) were the most common, followed by two video image training (20%) and one Nintendo Wii program (10%). In most studies, driving simulators trained the cognitive and visual abilities of seniors and enhanced their abilities to cope with risk situations under various simulated circumstances. Other interventions were also reported to have a positive effect. For evaluating elderly drivers, the driving performance evaluation using a driving simulator was the most common; in addition, evaluations of attention, space-time ability, cognitive function, risk perception, depression and anxiety were also commonly used. We believe that it is appropriate to employ computer-based driving intervention programs for seniors to train and evaluate various domains. We expect that these interventions can be used as an effective tool for safe driving.

• Journal of Animal Science and Technology
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• v.61 no.2
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• pp.55-60
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• 2019

Colibacillosis is one of the major health problems in young piglets resulting in poor health and death caused by Escherichia coli producing F18 pili and Shiga toxin 2e. It is pivotal to reduce colibacillosis in weaned piglets to enhance production performance. In this study, we evaluated synbiotics as the gut health improvement agents in the mouse model challenged with Shiga toxin-producing E. coli (STEC) isolated from piglets. Prebiotic lactulose was formulated with each $5.0{\times}10^6CFU/mL$ of Pediococcus acidilactici GB-U15, Lactobacillus plantarum GB-U17, and Lactobacillus plantarum GB 1-3 to produce 3 combinations of synbiotics. A total of 40 three weeks old BALB/c mice were randomly assigned to 4 groups (n = 10): a control group and 3 synbiotics treated groups. Each treatment groups were daily administrated with $5.0{\times}10^6CFU/mL$ of one synbiotics for the first week, and every 3 days during the second week. All the mice were challenged with $8.0{\times}10^8CFU/mL$ of STEC 5 days after animals began to receive synbiotics. Mice treated with synbiotics based on Pediococcus acidilactici GB-U15 and Lactobacillus plantarum GB-U17 significantly improved daily weight gain compared to mice in other groups. While mice treated with GB-U15 showed better fecal index, no significant differences were observed among groups. Gross lesion and histopathological evaluations showed that mice treated with GB-U15 moderately improved recovery from STEC infection. In conclusion, our results suggest that the synbiotics formulated with lactulose and Pediococcus acidilactici GB-U15 have potential benefits to prevent and improve colibacillosis in weaned piglets.