• IE interfaces
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• v.12 no.4
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• pp.496-505
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• 1999

Quality of Service(QoS) is the collective effect of service performances and has a direct impact on customer satisfaction. Although QoS is subjective, network performance parameters contributing to QoS can be measured physically. Therefore overall customer satisfaction for each test condition of the performance parameters is evaluated by asking respondents to indicate his or her opinion on a five-category rating scale i.e., excellent, good, fair, poor, and unsatisfactory. The opinion data resulting from the test can then be used to measure and analyze QoS from the customers' viewpoints. In this papaer, we consider two methods for analyzing the opinion data: MOS method and Cumulative Probability Curve method. The former evaluates an arithmetic mean of the opinion scores which quantify the surveyed opinions of respondents. The latter uses graphical and analytical models which are based on the distribution of the opinions rather than an arithmetic mean. The advantages, disadvantages, and an alternative of each method are discussed, together with future directions of research.

• Journal of the Korean Society of Safety
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• v.14 no.4
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• pp.78-84
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• 1999

A compact air-preheating type heat exchanger was developed and tested for the ultra-high temperature heat recovery applications. For the direct use of exhaust gases up to $1200^{\circ}C$, the heat exchanger adopted a ceramic core with high strength and low thermal expansion coefficient less than $1{\times}10^{-6}^{\circ}C^{-1}$. The ceramic core was fabricated by special extrusion and bonding techniques. To minimize thermal stresses in the core, spring-loaded sealing mechanism was designed and successfully installed. 1-pass air flow scheme was adopted for the compactness and cost-savings. The pressure test for the ceramic core showed no failure under 35 kPa and less than 3% leak under 7 kPa. Flue gas simulation system was developed to investigate the performance of the heat exchanger. The test results showed normal operations of the heat exchanger up to $1200^{\circ}C$ of exhaust gases and relatively high heat recovery efficiencies of 31～39% depending upon exhaust gas temperatures..

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.204-207
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• 2007

DMFC(direct methanol fuel cell)는 액체연료의 이동과 저장의 용이성 때문에 이동용 장치를 위한 전원공급 장치로서 오랫동안 관심을 받아왔다. 하지만 methanol crossover는 DMFC의 상용화 이전에 해결해야 할 문제이다. 이를 위해 많은 분야에서 연구가 진행되고 있고, 그중에서 methanol에 저항성을 가진 촉매의 개발에 활발히 연구가 진행되고 있다. 본 연구에서는, 표연개질 된 PtCo/C 촉매를 사용하여 메탄올에 저항성을 가진 촉매를 합성하였다. 합성된 촉매의 size와 morphology를 알아보기 위해 transmission electron microscopy (TEM)를 사용하였다. 또한 methanol 존재 하에 산소환원반응의 activity를 알아보기 위해 Rotating ring disk electrode(RRDE) test를 하였고, MEA를 제작하여 full cell test도 병행하였다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.05a
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• pp.141-144
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• 2000

The slope stability of waste landfill has been a problem in domestic and foreign countries. Waste landfills are being constructed in a reclaimed land or mountainous area. But most of these places are consisted of steep slope and hence it is necessary to use the geosynthetic liners in there. The large size direct shear test(30cm x 30cm) equipment was used to determine the interface friction angles between CCLs and soil & geomembranes. The centrifuge model tests were performed to investigate the slope stability with considering various geosynthetic liners conditions and degree of slope. The results of centrifuge model test indicate that the degree of saturation of GCL, roughness of geomembrane, and slope of landfill have greatly influenced on the slope stability of solid waste landfill.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.4
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• pp.262-264
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• 2005

A study on genetic variability and association of yield attributing characters with grain yield was carried out using 35 deepwater rice genotypes. High genotypic co-efficient of variation (GCV) was observed for plot yield, $EBT/m^2$, plant height and days to $50\%$ flowering (DFF). For all the traits, estimates of the phenotypic co-efficient of variation (PCV) were higher than GCV, indicating presence of environmental influence. High heritability and genetic advance was observed for plot yield, $EBT/m^2$ and plant height. Plot yield had significant positive association with test weight, $EBT/m^2$ and DFF. However, test weight had the maximum direct effect on grain yield

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.6
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• pp.106-114
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• 2000

In order to evaluate the shear characteristics of undisturbed weathered granite soil which is a typical residual soil in Korea, the mechanical properties are first investigated and discussed by carrying out a series of direct shear test and then dilatancy correction is performed by using Taylor’s correction equation. In this study, specimens are sampled at Pungam(-3, -8, -13m below ground surface), Kwangju and Iksan(-5m below ground surface), Jeonbuk. The test results are summarized as follows: 1) Mohr-Coulomb failure criterion is not linear under the low confining pressure. 2) The value of cohesion is smaller than usually determined value in low pressure region. 3) The value of strength parameter c and ø which are corrected by Taylor’s correction equation is a little bit small.

• The Journal of Korea Robotics Society
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• v.4 no.1
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• pp.49-55
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• 2009

The development of IT technology makes the functions and services of robots be integrated, and thus the robots become more intelligent and useful. As sophisticated usage of robots has evolved, direct communication by human language is necessary to increase the efficiency of their usage. In this paper, we propose a conversational interface platform for integrated service robots using MS Robotics Studio. The proposed platform consists of three types of components: a conversation manager to control the flows of the integrated service robots, a user interface to interact with users, and multiple service robots to perform actions or services. For a test-bed of the proposed platform, we build a schedule manager system and confirm the usability through SUS subject test by comparing the schedule manager system with MS Outlook.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.7
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• pp.66-75
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• 1999

Many researchers have developed the measurement technique of in-cylinder flow. Recently, there are lots of studies on steady flow with different SCV geometries. In this study the flow characteristics of four-valve cylinder head were examined in a steady test rig for different SCV open ratios. Each swirl ratio of several SCV angle was quantified by swirl impulse meter and 2D-LDV measurement. The results showed that the swirl ratio was controlled between 2.3 and 3.8 based on SCV angles. The velocity distributions of in-cylinder flow field were measured by 2-D LDV test and visualized swirl and tumble flow pattern at different positions. In this engine , we found out that the swirl was dominant flow.

• Journal of Biomedical Engineering Research
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• v.9 no.2
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• pp.171-178
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• 1988

In this study, we proposed a test to explore the function of Vestibulo-ocular reflex (VOR) which subjected to an angular head acceleration using pseudo random binary stimulus. Resultant eye movements(horizontal vestibular nystagmus) were digitized, filtered and transformed into the frequency domain. At first we evaluated the transfer function of V.0.R(gain and phase) and the coherence function between stimulus and response by linear frequency methods in view of the quantitative analysis since the vestibulo-ocular reflex can be considered as a linear system. at least, in normals. Secondly. with the proposed test, we showed a direct possibility that we could interpret the pathological situation quantitatively as an illustration of clinical application.

• Steel and Composite Structures
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• v.19 no.4
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• pp.789-809
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• 2015

This paper presents experimental and numerical studies into the structural behavior of a high performance corbel type composite connection adopted in Raffles City of Hangzhou, China. Physical tests under both monotonic and quasi-static cyclic loads were conducted to investigate the load carrying capacities and deformation characteristics of this new type of composite connection. A variety of structural responses are examined in detail, including load-deformation characteristics, the development of sectional direct and shear strains, and the history of cumulative plastic deformation and energy. A three-dimensional finite element model built up with solid elements was also proposed for the verification against test results. The studies demonstrate the high rigidity, strength and rotation capacities of the corbel type composite connections, and give detailed structural understanding for engineering design and practice. Structural engineers are encouraged to adopt the proposed corbel type composite connections in mega high-rise buildings to achieve an economical and buildable and architectural friendly engineering solution.