• Metals and materials international
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• v.24 no.6
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• pp.1249-1255
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• 2018

High temperature compression tests for newly developed Al-Zn-Mg alloy were carried out to investigate its hot deformation behavior and obtain deformation processing maps. In the compression tests, cylindrical specimens were deformed at high temperatures ($300-500^{\circ}C$) and strain rates of 0.001-1/s. Using the true stress-true strain curves obtained from the compression tests, processing maps were constructed by evaluating the power dissipation efficiency map and flow instability map. The processing map can be divided into three areas according to the microstructures of the deformed specimens: instability area with flow localization, instability area with mixed grains, and stable area with homogeneous grains resulting from continuous dynamic recrystallization (CDRX). The results suggest that the optimal processing conditions for the Al-Zn-Mg alloy are $450^{\circ}C$ and a strain rate of 0.001/s, having a stable area with homogeneous grains resulting from CDRX.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.12
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• pp.1142-1151
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• 2015

In this paper, High performance torque control based on the flux mapping of 48V Wound Rotor Synchronous Motor has been studied to improve torque control. Flux map considering MTPA (Maximum Torque Per Ampere), MFPT (Minimum Flux Per Torque), Maximum efficiency point at the same torque command and flux command for each field current was produced. Current map using flux mapping of Each field current was applied to the MTPA, MFPT. Generating a current vector locus was to determine the characteristics of the operation region. Through the Matlab/Simulink simulation, difference between speed-torque map and flux map was represented. The suggested flux map was tested actual experiments on a dynamometer.

• Preventive Nutrition and Food Science
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• v.19 no.2
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• pp.69-74
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• 2014

The present study investigated the anti-obesity effects of Mycoleptodonoides aitchisonii (MA) in mice fed a high-fat (HF) diet. Two groups were fed either a normal control diet or an HF (45% kcal fat) diet for 12 weeks and three groups were fed an HF diet supplemented with powdered MA (MAP, 1%, 3%, and 5%) for 12 weeks. The anti-obesity effects of MAP supplementation on body weight, fat mass development, and lipid-related markers were assessed. Consumption of an HF diet resulted in increased body weight, serum lipids, relative adipose tissues weight, and liver fat accumulation. However, administration of MAP significantly decreased body weight gain, food intake, food efficiency ratio, hepatic cholesterol level, and adipose tissue weight in a dose-dependent manner. In addition, treatment with MAP significantly reduced the occurrence of fatty liver deposits and steatosis, and inhibited an HF diet-induced increase in adipocyte size. These results suggest that dietary supplementation with MAP exerts anti-obesity effects and indicate that MAP could be used as a functional food to control obesity.

• Journal of Information Processing Systems
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• v.13 no.4
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• pp.668-676
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• 2017

Recently, the importance of big data has been emphasized with the development of smartphone, web/SNS. As a result, MapReduce, which can efficiently process big data, is receiving worldwide attention because of its excellent scalability and stability. Since big data has a large amount, fast creation speed, and various properties, it is more efficient to process big data summary information than big data itself. Wavelet histogram, which is a typical data summary information generation technique, can generate optimal data summary information that does not cause loss of information of original data. Therefore, a system applying a wavelet histogram generation technique based on MapReduce has been actively studied. However, existing research has a disadvantage in that the generation speed is slow because the wavelet histogram is generated through one or more MapReduce Jobs. And there is a high possibility that the error of the data restored by the wavelet histogram becomes large. However, since the wavelet histogram generation system based on the MapReduce developed in this paper generates the wavelet histogram through one MapReduce Job, the generation speed can be greatly increased. In addition, since the wavelet histogram is generated by adjusting the error boundary specified by the user, the error of the restored data can be adjusted from the wavelet histogram. Finally, we verified the efficiency of the wavelet histogram generation system developed in this paper through performance evaluation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.20-29
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• 2018

Owing to the changing climate and recent flood events, flood damage caused by river levee collapse and overflow is on the rise in Korea, making it necessary to enhance river levee maintenance technologies to deal with various flood damage scenarios. This paper proposes the evaluation system of a river-levee safety map to improve maintenance efficiency and disaster responsiveness. A river-levee safety map, indicating sliding, piping, visual inspection, scouring, and safety index of a levee fill material on a GIS map will enable the dangerous zone to be identified visually and the development of proactive measures to deal with it. This will maximize the river-levee maintenance efficiency, which is a break from traditional practice in that restoration measures are taken only after the damage has occurred. This study includes scouring and levee fill material in addition to previously-proposed sliding, piping and visual inspections. The research activities conducted in the study include 1) categorization of scouring and levee fill material based on document and data examination, 2) evaluation of sliding and piping at 5 locations on the left levee in the Nam river according to the duration time of the flood water level, and 3) evaluation of the characteristics of scouring and levee fill material at 9 locations on the left/right levee in the Nam River. The river levee safety map proposed in this study would be more useful and practical but further study on the manual for river management organization, repair and reinforcement methods, and budget is required.

• Journal of the Korea Society of Computer and Information
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• v.18 no.4
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• pp.27-34
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• 2013

Mobile robot has the exploration function in order to perform its own task. Robot exploration can be used in many applications such as surveillance, rescue and resource detection. The workspace that robots performed in was complicated or quite wide, the multi search using the several mobile robots was mainly used. In this paper, we proposed a scheme that all areas are searched for by using one robot. The method to be proposed extract a area that can be explored in the workspace then the robot investigates the area and updates the map at the same time. The explored area is saved as a hybrid map that combines the nice attributes of the grid and topological maps. The robot can produce the safe navigation route without the obstacles by using hybrid map. The proposed hybrid map uses less memory than a grid map, but it can be used for complete coverage with the same efficiency of a topological map. Experimental results show that the proposed scheme can generate a map of an environment with only 6% of the memory that a grid map requires.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.8
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• pp.1637-1646
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• 2009

Recently many researchers have been studying various methods for data integration. Among the integration methods that the researchers have studied, there are a method using metadata repository, and Topic Map which identifies the relationships between the data. This study suggests Meta-Topic Map to create Topic Map about search keyword by applying metadata and Topic Map, and the XMDR as a way to connect Meta-Topic Map with metadata in the legacy system. Considering the semantic relationship of user's keyword in the legacy system, the Meta-Topic Map provides the Topic Map format and generates the Topic Map about user's keyword. The XMDR performs structural integration through solving the problem of heterogeneity among metadata in the legacy system. The suggested svides isproves the interoperability among existing Relational Database constructed in the legacy system and the search efficiency and is efficient in expanding the system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.4
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• pp.417-425
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• 2013

Digital communication technology have been focused on the higher data efficiency and the effective coding of information. Also, it is very important to improve security and minimize the interference of the external sources, Chaos communications system is studied to improve security and minimize the interference by effective encoding of information in the nonlinear systems such as DCSK(Differential Chaos Shift Keying) and CDSK(Correlation Delay Shift Keying). In this paper, we evaluate anti-jamming performance of chaos communications system using the DCSK and CDSK system. The simulation results show that the Gauss iterated map has better BER performance than the other maps(tent map, logistic map, Henon map). Also, DCSK and CDSK system can get the better anti-jamming performance by applying different chaotic maps.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.5
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• pp.20-30
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• 2007

Environmental Conservation Value Assessment Map (ECVAM) is the class map to divide the national land into conservation areas and development areas based on legal and ecological assessment criteria. It contributes to enhancements of the efficiency and the scientificity when framing a policy in various fields including the environment. However, it is impossible to understand the multiphase vegetation structure as data on judging the national forest class in ECVAM are restricted to areal information of Ecological Nature Status, Degree of Green Naturality and Forest Map. This point drops the reliability of ECVAM. Therefore we constructed vegetation information using LiDAR (Light Detection And Raging) technology. We generated Biomass Class Maps as final results of this study, to introduce the new forest assessment criterion in ECVAM that alternates or makes up for existing forest assessment criteria. And then, we compared these with Forest Map and Landsat TM NDVI image. As a result, biomass classes are generally higher than stand age classes and DBH classes of Vegetation Map, and lower than NDVI of Landsat TM image because of the difference of time on data construction. However distributions between these classes are mostly similar. Therefore we estimates that it is possible to apply the biomass item to the new forest assessment criterion of ECVAM. The introduction of the biomass in ECVAM makes it useful to detect the vegetation succession, to adjust the class of the changed zone since the production of Vegetation Map and to rectify the class error of Vegetation Map because variations on tree heights, forest area, gaps between trees, vegetation vitality and so on are acquired as interim findings in process of computing biomass.

• Spatial Information Research
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• v.15 no.2
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• pp.123-134
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• 2007

The building boundary should be registered in the cadastral map for the protection of property using the expansion of the registration items in the cadastral record and the construction of 3D-cadastral information system. In this study, the efficiency of registering the building boundary was suggested by non-target TS survey through the comparison between target TS and non-target TS survey about an accuracy and efficiency. At the result of this research, the RMSE of target TS and non-target TS survey is the X; ${\pm}0.056m$ and Y; ${\pm}0.043m$. Therefore, non-target TS survey shows the high accuracy. Also, the non-target TS survey is more efficient cost on time and personnel than target TS.