• KIPS Transactions on Software and Data Engineering
• /
• v.6 no.10
• /
• pp.487-492
• /
• 2017

Clustering is a technique which is used to measure similarities between data in big data analysis and data mining field. Among various clustering methods, k-Modes algorithm is representatively used for categorical data. To increase the performance of iterative-centric tasks such as k-Modes, a distributed and concurrent framework Spark has been received great attention recently because it overcomes the limitation of Hadoop. Spark provides an environment that can process large amount of data in main memory using the concept of abstract objects called RDD. Spark provides Mllib, a dedicated library for machine learning, but Mllib only includes k-means that can process only continuous data, so there is a limitation that categorical data processing is impossible. In this paper, we design RDD for k-Modes algorithm for categorical data clustering in spark environment and implement an algorithm that can operate effectively. Experiments show that the proposed algorithm increases linearly in the spark environment.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.17 no.5
• /
• pp.640-647
• /
• 2007

This paper presents a joint controller for a humanoid robot based on genetic algorithm. h humanoid robot has basically instability during walking because it isn't fixed on the ground. Moreover nonlinearities of the joints increase its instability. If one of them isn't satisfied, the robot may fall down at the ground during walking. To attack one of those problems, joint controller is proposed. It can perform tracking control preciously and reduce the effect of nonlinearities by gear, limitation of the input voltage, coulomb friction and so on. This controller is based on fuzzy-sliding mode controller (FSMC) and compensator and control gains are searched by a proposed genetic algorithm. It can reduce the effect by nonlinearities. Also, to improve the tracking performance, the proposed controller has motion controller. From the given controller, a humanoid robot can moved more preciously. Here, all the processes are investigated through simulations and it is verified experimentally in a real joint system for a humanoid robot.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2016.05a
• /
• pp.194-194
• /
• 2016

Gansu, located in the northwestern region, is a typical agricultural province of arid, semiarid in China. The shortage of water resources is the biggest obstacle of Gansu Province's development, and the dry farming water-saving is the eternal theme of Gansu agricultural sustainable development. In recent years, intensify reform in Gansu, has walked out a successful way in the agricultural water-saving. Using the integrated river basin governance as opportunity, the total water-using quantity was regarded as rigidity to retrain, distributed to counties (districts), irrigated areas, towns, associations, groups step by step. Agricultural water price was substantially increased, with the surface water price from about $0.1RMB/m^3$ to more than $0.2 RMB/m^3$, and the ground water from zero to more than $0.1RMB/m^3$. Simultaneously, the difference water prices and over-quota water progression price markup were carried out. The transaction of water rights was encouraged to impel the peasant to establish the consciousness of saving-water. The regulatory documents were formulated to standardize the scope, condition, mode, program etc. of agriculture water-rights transaction, to guarantees the transaction of water rights is carries out in order. The pattern of farming was optimized and adjusted, reducing the high water-consumption crop, increasing economic crops with high benefit and low water-consumption, developing industrialized agricultures such as green house. The relative engineering and measuring facility were comprehensively improved, with the anti-seepage of canal system and the enforcement of dynamo-electric well, developing high-efficient water-saving irrigation and overall metering facilities. The water fine-grained management has realized, and obvious water-saving effect has obtained: water-using rate in the irrigation area by river water has brought up to 0.57 from 0.52, and by well water up to 0.84 from 0.76. Although the water price has increased, the proportion that the water rate expenditure accounted for the cost lasts decline, and the farmers' income has gone up. The peasants express, the used water is few, and it is few to till land, but the income is many, and life is better.

• Journal of Digital Convergence
• /
• v.19 no.12
• /
• pp.157-164
• /
• 2021

This study was conducted to investigate students' perception of the integration of Chinese ethnic minority culture into the college EFL teaching which was carried out in the fall and spring semesters with different presentation topics. One and the same questionnaire was distributed to 61 participants, involving Han Chinese and Chinese ethnic minority students, at a university in ethnic minority area in China at the end of each semester, and SPSS 20.0 was used for t-test to analyze the data. The research results showed that Chinese undergraduates have got more significant improvements in cultural cognition, emotions, attitudes, and multi-cultural values in the spring semester than those in the fall semester. All participants benefit a lot from multi-cultural activities without significant differences between Han Chinese and ethnic minority students in both semesters. It is suggested that ethnic minority culture be integrated into the college EFL teaching, along with English culture and Chinese mainstream culture, which be administered as a practical teaching mode to develop students' intercultural competence.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.26 no.2
• /
• pp.82-89
• /
• 2021

This study proposes a DAB two-stage series structure with insulated bidirectional DC-DC converter for two-way power transfer between the renewable energy of high voltages (1 kV and above). The proposed circuit transforms the existing DAB converter into a two-stage series structure to reduce the pressure in the switch. The problem of power imbalance occurring in the design of the DAB converter second-stage series is improved by applying the cell balancing method circuit and the common mode coupled inductor using an external flying capacitor instead of reflecting the existing improvement measures, voltage balance control, and inductor current control. In addition, a no-load supercharging sequence is proposed in high voltages and high-speed switching by using the fixed duty output method. This study presents the analysis results through the structure of the proposed circuit, the principle of improving the power imbalance problem, and simulations. Prototypes were manufactured to meet the specifications of input/output voltage of 1700 V, maximum load of 65 kW, and switching frequency of 51kHz, and the validity of the topology was verified using the experimental results and efficiency data.

• Journal of Convergence for Information Technology
• /
• v.8 no.6
• /
• pp.305-315
• /
• 2018

The purpose of this study is to investigate the relationship between university students' interest in appearance management and various forms of appearance management behaviors converged with beauty trends. The questionnaire was distributed for 15 days from April 15 to 30, 2018 to the students in the G district. The data of 267 students who explained and agreed on the purpose and method of the study were analyzed using SPSS 18. University students' interest in appearance management showed a difference of interest according to university students, male and female students in body composition management, skin care, hair care, and cosmetics use management except for interest in health care. In addition, students with a high level of interest in managing cosmetics use had a positive effect on the degree of interest in managing cosmetics usage in fashion styles, cosmetics style, skin care, and body management behavior factors that were converged with trends. And negative (-) influence on the use of health equipment. Based on the study of the trend management behaviors of college students, I will expect to utilize the reference materials for new product development research of the beauty industry and will continue to study the new management mode of appearance management.

• Journal of Powder Materials
• /
• v.26 no.3
• /
• pp.208-213
• /
• 2019

In this study, lanthanum oxide ($La_2O_3$) dispersed molybdenum ($Mo-La_2O_3$) alloys are fabricated using lanthanum nitrate solution and nanosized Mo particles produced by hydrogen reduction of molybdenum oxide. The effect of $La_2O_3$ dispersion in a Mo matrix on the fracture toughness at room temperature is demonstrated through the formation behavior of $La_2O_3$ from the precursor and three-point bending test using a single-edge notched bend specimen. The relative density of the $Mo-0.3La_2O_3$ specimen sintered by pressureless sintering is approximately 99%, and $La_2O_3$ with a size of hundreds of nanometers is uniformly distributed in the Mo matrix. It is also confirmed that the fracture toughness is $19.46MPa{\cdot}m^{1/2}$, an improvement of approximately 40% over the fracture toughness of $13.50MPa{\cdot}m^{1/2}$ on a pure-Mo specimen without $La_2O_3$, and this difference in the fracture toughness occurs because of the changes in fracture mode of the Mo matrix caused by the dispersion of $La_2O_3$.

• Journal of Ecology and Environment
• /
• v.45 no.1
• /
• pp.72-77
• /
• 2021

Background: In 2020, a categorized list of wetland preferences, major habitats, and life forms of 4145 vascular plant taxa occurring in the Korean Peninsula was published by the National Institute of Biological Resources. We analyzed the list and explored the distribution patterns of the five categorized groups according to wetland preference, along with the information on the major habitats and the life forms of the plants belonging to those categories. Results: Out of 4145 taxa, we found that 729 wetland plant taxa (18%) occur in Korea: 401 obligate wetland plants and 328 facultative wetland plants. Among the 729 wetland taxa, the majority (73%) was hygrophytes and the remaining 27% was aquatic macrophytes. Furthermore, almost all of the wetland taxa are herbs; so, woody plants are only 4.7%. The 16 carnivorous taxa distributed in Korea were characterized as obligate wetland plants. Conclusions: We expect the categorized information would promote understanding of the characteristics of the plant species and would be an important source for understanding, conservation, and restoration of wetland ecosystems.

• Journal of Advanced Navigation Technology
• /
• v.26 no.5
• /
• pp.331-337
• /
• 2022

The length of optical fiber in dispersion-managed link combined with optical phase conjugation to compensate for signal distortion caused by chromatic dispersion and nonlinear Kerr effect is a major factor determining the compensation effectiveness. The dispersion-managed link consists of several fiber spans in which standard single mode fiber and dispersion compensating fiber are arranged. In this paper, the compensation effect in the link that changes residual dispersion per span only by adjusting the length of one type of optical fiber, which is different in the first half link and the second half link with respect to optical phase conjugator (OPC), has been investigated. It was confirmed that the best compensation for 960 Gb/s wavelength division multiplexed signal could be obtained in the dispersion-managed link, in which the cumulative dispersion profile is symmetric around the OPC, and the cumulative dispersion amount is all positive in the first half, and all the cumulative dispersion amount is distributed negatively in the second half.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.17 no.2
• /
• pp.312-334
• /
• 2023

In large-scale computing, cloud computing plays an important role by sharing globally-distributed resources. The evolution of cloud has taken place in the development of data centers and numerous servers across the globe. But the cloud information centers incur huge operational costs, consume high electricity and emit tons of dioxides. It is possible for the cloud suppliers to leverage their resources and decrease the consumption of energy through various methods such as dynamic consolidation of Virtual Machines (VMs), by keeping idle nodes in sleep mode and mistreatment of live migration. But the performance may get affected in case of harsh consolidation of VMs. So, it is a desired trait to have associate degree energy-performance exchange without compromising the quality of service while at the same time reducing the power consumption. This research article details a number of novel algorithms that dynamically consolidate the VMs in cloud information centers. The primary objective of the study is to leverage the computing resources to its best and reduce the energy consumption way behind the Service Level Agreement (SLA)drawbacks relevant to CPU load, RAM capacity and information measure. The proposed VM consolidation Algorithm (PVMCA) is contained of four algorithms: over loaded host detection algorithm, VM selection algorithm, VM placement algorithm, and under loading host detection algorithm. PVMCA is dynamic because it uses dynamic thresholds instead of static thresholds values, which makes it suggestion for real, unpredictable workloads common in cloud data centers. Also, the Algorithms are adaptive because it inevitably adjusts its behavior based on the studies of historical data of host resource utilization for any application with diverse workload patterns. Finally, the proposed algorithm is online because the algorithms are achieved run time and make an action in response to each request. The proposed algorithms' efficiency was validated through different simulations of extensive nature. The output analysis depicts the projected algorithms scaled back the energy consumption up to some considerable level besides ensuring proper SLA. On the basis of the project algorithms, the energy consumption got reduced by 22% while there was an improvement observed in SLA up to 80% compared to other benchmark algorithms.