• The KIPS Transactions:PartC
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• v.10C no.1
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• pp.33-38
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• 2003

Most of the existing algorithms try to disseminate the multimedia contents of internet service provider (ISP), without taking into account characteristics and capacities of duplicated servers. However, they are less reliable without prior information on capacities of duplicated servers. In this paper we propose two algorithms, performance rating algorithm of hardware and capacity algorithm, inspired by the need of improving QoS of delivering multimedia contents without incurring long access delays when the capacities of duplicated servers are significantly different and clients locate in a fixed geographical domain Our simulation results show that they are better than HTTP response time algorithm when the multimedia contents are large and quite different from performances between duplicated servers.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.5
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• pp.992-1002
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• 1988

The dynamic response of rotor-bearing systems subjected to six-component nonststionary earthquake ground accelerations is analyzed. The governing equations of motion for the rotor are derived using Lagrangian approach. The six-component earthquake inputs result in both inhomogeneous and parametric excitations, so that the conventional spectral analysis of random vibration is not applicable. The method of Monte Carlo simulation is utilized to simulate the six-component nonstationary earthquake ground motions and to determine the response statistics of rotor-bearing systems. The significant influences due to rotational motions of seismic base on the overall structural response is demonstrated by a numerical example.

• Journal of Korean Orthopaedic Sports Medicine
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• v.5 no.2
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• pp.129-134
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• 2006

Purpose: In the professional soccer team, we performed pre-seasonal physical examination and analyzed the results to establish a standardization data in relation to their position. Materials and Methods: We performed physical examination to the professional soccer team, consisted 34 player's average age 24.9 years. The examination performed were questionnaire on history, musculoskeletal examination, muscle power test, physiologic test, functional test. Results: According to the relationship between player position and injury pattern,. Knee injuries are most frequent on history. Physical examination outcome was that forward were prone to flexor hallucis longus tendinitis, midfielder for chronic ankle instability, defender for achilles tendinitis. Isokinetic test was done at dominant side, Peak torque to body weight ratio was 55.1%. Physiologic test checked body fat percentage was midfielder was superior as 19.8 (SD 2.9). Functional test out-come was that back strength 125 N. sergeant jump 59.6 cm, reaction time 208.5 sec, flexibility 19.2 m/s, side step 39.9 cm. Conclusion: Pre-seasonal physical examination gave us the standardization data and preventive measurement could be advocated from this results.

• Design Convergence Study
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• v.16 no.6
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• pp.123-135
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• 2017

In recent mobile health care service, health management using number of steps is becoming popular. In addition, a variety of activity trackers have made it possible to measure the number of steps more accurately and easily. Nevertheless, the activity tracker is not popularized, and it is a trend to use the pedometer sensor of the smartphone as an alternative. In this study, we tried to find out how much the number of steps collected by the smartphone versus the actual number of steps in actual situations, and what factors make the difference. We conducted an experiment to collect number of steps data of 21 people using the smartphone and wearable device simultaneously for 7 days. As a result, we found that the average number of steps of the smartphone is 62% compared to the actual number of steps, and that there is a large variation among users. We derived a regression model in which the accuracy of smartphone increases with the degree of awareness of smartphone. We expect that this can be used as a factor to correct the difference from the actual number of steps in the smartphone alone healthcare service.

• Analytical Science and Technology
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• v.21 no.4
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• pp.272-278
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• 2008

Methods to separate 14 rare earth elements (REEs) and yttrium by the $AG^{(R)}$ 50W-X8 cation exchange resin, and to determine REEs by inductively coupled plasma atomic emission spectrophotometry (ICP-AES) were described. Ion exchange capacities of REEs on the resin were so high that the REEs were quantitatively ion exchanged under the flow rate of 0.3~1.0 mL/min at pH 1~6. The breakthrough capacity curve of the REEs showed that ion exchange capacities of light REEs (Cerium group) were greater than that of the heavy REEs (Yttrium group). When $200{\mu}g$ of each REEs was ion exchanged on 100 mg of resin, most of the heavy REEs were quantitatively desorbed with 10 mL of 2.0 M of $HNO_3$, while most of the light REEs with 30 mL. The method was applied to the monazite sample. The REEs could be separated from matrix, since ion exchange capacities of matrix ions of Ca, Ti, Mg, Mn were much lower than that of the REEs. However the relative standard deviations of the analytical results by the present method were not improved, as high as 1~5%.

• Analytical Science and Technology
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• v.29 no.2
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• pp.57-64
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• 2016

Many phthalic acid esters (PAEs), including DMP, DEP, DBP, BBP, and DEHP, as well as DEHA are widely used as plasticizers in plastics. An analytical method was developed and used to analyze these compounds at 41 industrial facilities. The coefficient of determination (R²) for each constructed curve was higher than 0.98. The method detection limit (MDL) values were 0.4–0.7 μg/L for PAEs and 0.6 μg/L for DEHA. In addition, the recovery rate was shown to be 77.0–92.3%, while the relative standard deviation was shown to be in the range of 5.8-10.5%. DMP (n = 3), DEP (n = 2), DBP (n = 2), BBP (n = 2), and DEHA (n = 3) were detected in the range of 2.2-11.1% in the influent. DEHP was a predominant compound and was detected at > MDL in both the influent (n = 16, 35.6%) and the effluent (n = 4, 10.0%) at a high removal efficiency (92–100%). The highest levels of residue in industrial wastewater influent were 137.4 μg/L of DEHP at plastic products manufacturing facility, 12.5 μg/L of DEHA at a chemical manufacturing facility, and 14.0 μg/L of DEP at an electronics facility. The highest concentration of effluent was 12.5 μg/L of DEHP at a chemical manufacturing facility, which indicated that the effluent was below the allowable concentration (800 μg/L). Therefore, the levels of PAEs and DEHA that are discharged into nearby streams could not influence the health of the ecosystem.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.1871-1878
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• 2014

PMMA (Polymethyle-methacrylate) optical components have recently been increasingly used as one of the important part of the high precision equipments. This research presents comparatively the surface preparation of light incident plane, LIP (Light Incident Plane) of LGP (Light Guide Panel) by end milling, high speed shaping, and vibration assisted high speed shaping. From several experiments, the results show that the surface quality was improved in high speed shaping and the vibration assisted HSS show not only decreasing waviness and breakage also raising the straightness property. For applying high speed shaping and vibration assisted HSS, an additional tool post was developed and experimentally used.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2351-2357
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• 2013

An index was developed for analyzing the promising countries for seawater desalination plant and related data sets were collected and analyzed. Each indicators was standardized by scale readjustment method and Delphi method was used to calculate the weights for indicators from questionnaire survey by experts in seawater desalination plant field. Twenty three indicators were selected and they were classified into three groups, economic, social, and environmental indicator groups. Eleven countries (Saudi Arabia, UAE, Kuwait, Iran, Qatar, China, Singapore, India, Algeria, Turkey, United States) were selected considering present data availability and index for each country was calculated. The results show United States and China took the first (0.537) and second (0.490) place for the most promising country for seawater desalination plant. However it will not be easy to play a significant role in the markets because of present seawater desalination technology level and national policy, etc. Saudi Arabia took the third (0.329) place and other countries which has more than 0.2 index value can be considered as a promising countries for seawater desalination plant. We can establish a strategy to export our seawater desalination technology and plant using the result of this study. The developed index can be applied to other countries, which were not included in this study, when their data is available.

• Journal of the Korean Chemical Society
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• v.52 no.2
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• pp.140-147
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• 2008

.A new approach for a cloud point extraction-electrothermal atomic absorption spectrometric method was used for determining bismuth. The aqueous analyte was acidified with sulfuric acid (pH 3.0-3.5). Triton X-114 was added as a surfactant and natriumdiethyldithiocarbaminat (Na-DDTC) was used as a complexing agent. After phase separation at 50oC based on the cloud point separation of the mixture, the surfactant-rich phasen was diluted using tetrahydrofuran (THF). Twenty microliters (20 L) of the enriched solution and 10 l of 0.1% (w/v) Pd(NO3)2 as chemical modifier were dispersed into the graphite tube and the analyte determined by electrothermal atomic absorption spectrometry. After optimizing extraction conditions and instrumental parameters, a preconcentration factor of 195 was obtained for a sample of only 10 mL. The detection limit was 0.04 ng ml-1 and the analytical curve was linear for the concentration range of 0.04-0.70 ng mL-1. Relative standard deviations were <5%. The method was successfully applied for the extraction and determination of bismuth in water samples.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.2
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• pp.1-5
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• 2007

Wavelength-division multiplexed (WDM) networks are emerging to be the right choice for the future transport networks. In WDM networks, the optical layer provides circuit-switched lightpath services to the client layer such as IP, SONET and ATM. The set of lightpaths in the optical layer defines the virtual topology. Since the optical switches are reconfigurable, the virtual topology can be reconfigured in accordance with the changing traffic demand pattern at theclient layer in order to optimize the network performance. We present a new approach to the virtual topology reconfiguration and loadbalancing problem for wavelength-routed, optical wide-area networks under dynamic traffic demand. By utilizing the measured Internet backbone traffic characteristics, our approach follows the changes in traffic without assuming that the future traffic pattern is known. For the simulation traffic modeling, we collected the data from real backbone traffic. Experiments show that the standard deviation compared to previous technique is reduced.