• Journal of Institute of Control, Robotics and Systems
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• v.6 no.7
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• pp.602-610
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• 2000

In communication networks used in safety-critical systems such as control systems in nuclear power plants there exist three types of data traffic : urgent or asynchronous hard real-time data hard real-time periodic data and soft real-time periodic data. it is necessary to allocate a suitable bandwidth to each data traffic in order to meet their real-time constraints. This paper proposes a method to meet the real-time constraints for the three types of data traffic simultaneously under a timer-controlled token bus protocol or the IEEE 802.4 token bus protocol and verifies the validity of the presented method by an example. This paper derives the proper region of the high priority token hold time and the target token rotation time for each station within which the real-time constraints for the three types of data traffic are met, Since the scheduling of the data traffic may reduce the possibility of the abrupt increase of the network load this paper proposes a brief heuristic method to make a scheduling table to satisfy their real-time constraints.

• Journal of Soil and Groundwater Environment
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• v.13 no.1
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• pp.43-51
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• 2008

Periodic fluctuation of water levels were analyzed for their causes and effects on groundwater movement. Groundwater levels were monitored from two shallow monitoring wells, G1 and G4, located at a headwater catchment in the Gwangneung Ecohydrological Research Site using pressure transducers with automatic data-loggers by five-minute interval from February to October, 2006. The water table fluctuates on a daily basis with a clear diurnal variation, and the fluctuation amplitude increases with time from the winter to the summer. Results from spectral analysis of water-level data show periodic variations in 24.38 hour and in 12.19 hour, indicating $P_1$ diurnal and $L_2$ semidiurnal tidal components, respectively. The diurnal component of the water level in summer has greater power than that in winter, implying that the water table is affected not only by earth tides, but also by evapotranspiration. Right after rain stops, the power of diurnal component of the water level decreases, indicating that evapotranspiration influences significantly diurnal periodicity. The effects of diurnal and semidiurnal components of the water level range from 0.4 to 4.2 cm and from 0.2 to 0.7 cm, respectively.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.5 no.4
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• pp.286-290
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• 2005

We consider the poisson equation where the functions involved are periodic including the solution function. Let $R=[0,1]{\times}[0,l]{\times}[0,1]$ be the region of interest and let $\phi$(x,y,z) be an arbitrary periodic function defined in the region R such that $\phi$(x,y,z) satisfies $\phi$(x+1, y, z)=$\phi$(x, y+1, z)=$\phi$(x, y, z+1)=$\phi$(x,y,z) for all x,y,z. We describe a very simple method for solving the equation ${\nabla}^2u(x, y, z)$ = $\phi$(x, y, z) based on the cubic spline interpolation of u(x, y, z); using the requirement that each interval [0,1] is a multiple of the period in the corresponding coordinates, the Laplacian operator applied to the cubic spline interpolation of u(x, y, z) can be replaced by a square matrix. The solution can then be computed simply by multiplying $\phi$(x, y, z) by the inverse of this matrix. A description on how the storage of nearly a Giga byte for $20{\times}20{\times}20$ nodes, equivalent to a $8000{\times}8000$ matrix is handled by using the fuzzy rule table method and a description on how the shape preserving property of the Laplacian operator will be affected by this approximation are included.

• Journal of Science Education
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• v.39 no.1
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• pp.15-27
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• 2015

This study investigated whether there was a difference of the change in perspective of the nature of science depending on subjects of the history of science, after designing for two kinds of topics of role play programs based on the history of science to be transformed into a modern perspective. Before the history of science-role plays, the degree of the modern perspective was statistically no difference between group I(the atomic model transition-role play) and group II(the Mendeleev's periodic table-role play). However after treatment of the history of science-role plays for the each group, the degree of group I was higher than the degree of group II in the modern perspective. The results of this study indicate that the degree of changes into modern perspective of the nature of science by performing a history of science-role play may be depend on the subject of the history of science combined with the role play, and suggest the possibility that may be more effective to change the nature of science into the modern perspective, in case of performing of role play based on the history of science that includes the scientific knowledge established by a number of scientists with time series.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10B
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• pp.1867-1875
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• 1999

This paper presents a very unique and analytic method for scheduling messages routed through a non-blocking switch. The laxities of schedulable messages are decomposed and the laxity table is rearranged so that the packets to be scheduled in the next time instance are placed in the diagonal of the traffic matrix. And the modified MLF-SDR algorithm is performed on the table. We present some examples and simulation results which show that the success rate is very high, even when the size of which is large.

• Journal of Preventive Medicine and Public Health
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• v.20 no.2 s.22
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• pp.270-279
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• 1987

In all enterprises of Korea employing workers more than five, employeers have a duty of conducting a periodic health screening for improvement and maintaining healthful living and working conditions of employees. The health screening is performed annually in line workers and biennially in table workers under the supervision of the government. But there are some argument to the health screening programme in view of effectiveness, efficiency, reliability and etc. In order to obtain basic reference materials for increasing the efficiency of peridoic health screening programme for workers and understand the attitude of health screening institutions and enterprises toward the periodic health screening, mail questionnaire survey was conducted in July 1987. The questionnaire sent to 950 health screening institutions. and 700 enterprises in whole land but they were returned from 254 health istitutions and 187 enterprises, which were analyzed. The results were as follows: 1) The attitude of the respondents toward the necessity and benefit of the periodic health screening was showed highly positive responses in both of screening institutions and enterprises, and it was more positive in screening institutions. The attitude toward the affirmative and the contentment was showed less positive than that of the necessity and benefit. 2) The respondent recognized may problems on regard to the screening programme. The health screening institutions lie in the state of competition with other institutions for undertaking the screening programme. 3) One of major complaints from enterprises was the lack of sincerity in performing the screening programme. They wanted more practical and reliable health screening examination rather than showy one. 4) Health screening institutions and enterprises showed some mutual contradictions in the matter of screening fee, and so the screening fee should be adjusted to the appropriate cost.

• Journal of Biomedical Engineering Research
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• v.44 no.1
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• pp.1-10
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• 2023

With the announcement of MEDICAL DEVICE REGULATION 2017/745 (MDR) on April 5 2017, medical device manufacturers shall apply ISO 14971:2019 (3^rd) revised in December 2019. However, there is not much related information and guidance available to medical device manufacturers, especially single use medical device. Risk management process basically follow 5 steps which are Risk Analysis, Risk Evaluation, Risk Control, Evaluation of overall residual risk and post-production activities. The purpose of this study is to provide a guidance of from risk analysis with Failure Mode and Effects Analysis (FMEA) table to overall residual risk evaluation for the single use medical device and to reflect it in a Periodic Safety Update Reports (PSUR) to satisfy with MDR requirements with single use medical device which are widely used and manufactured FDA class 2 or CE class IIb as examples. For this study, single use medical device manufacturer can adopt ISO 14971:2019 in accordance with MDR requirements and it can be extended to the PSUR. But there are still limitations to adopt to the all-single use medical device especially high class, private device and implantable device. So, Competent Authority (CA) shall publish more guidance for the single use medical device.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.115-133
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• 2010

For assessment of U-Eco City technologies, more concrete definition of those technologies are required. However, almost researches defined technologies as conceptually and even cannot include all of them. In this sense, the purpose of this study is to deduct assessing items for specifying applying priority of U-Eco City technologies. We performed the research by 3 steps. Firstly, we deduct assessing items of the technologies by researching their advance process. After then, we compensate the defect of those items through documentary research and made a periodic table about core technologies that can be useful for deducting long-term items. The assessing items what are deducted as a result of this study can be applied to the selection of technology, and will be useful to construct more objective and systematized U-Eco City. Furthermore, if assessment frame about technologies and services is developed from this research, it gives to us probability that standardized process of U-Eco City construction can be established.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.2
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• pp.338-348
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• 1988

This study presents an analysis of periodic heat diffusion in an annular fin with uniform thickness. When the temperature of the fin base is changed in the form of a sinusoidal function, the exact temperature solution can be obtained by Laplace transformation in terms of the dimensionless parameters in the infinite series. Local heat flux and average heat flux, local fin efficiency and average fin efficiency were obtained. Particularly, the table of eigenvalues that are the indispensable condition in solving the heat transfer problem of annular fin in a transient state with convection phenomena at the fin edge is provided. The tables of heat fluxes and average heat fluxes, fin efficiencies and average fin efficiencies are also provided from the computed results. Also, substituting the variations of dimensionless parameters into the these exact solutions, the characteristics of these response are investigated.

• The KIPS Transactions:PartA
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• v.14A no.1 s.105
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• pp.63-72
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• 2007

This paper introduces a load-balancing algorithm focusing on distributing web requests evenly into the web cluster servers. The load-balancing algorithms based on conventional periodic load-information update mechanism are not suitable for dynamic page applications, which are common in Cyber Foraging services, due to the problems caused by periodic synchronized load-information updating and the difficulties of work load estimation caused by embedded executing scripts of dynamic pages. Update-on-Finish algorithm solves this problem by using non-periodic load-update mechanism, and the web switch knows the servers' real load information only after their reporting and then distributes new loads according to the new load-information table, however it results in much communication overhead. Our proposed mechanism improve update-on-finish algorithm by using K-Percents-Finish mechanism and thus largely reduce the communication overhead. Furthermore, we consider the different capabilities of servers with a threshold Ti value and propose a load-balancing algorithm for servers with various capabilities. Simulation results show that the proposed K-Percents-Finish Reporting mechanism can at least reduce 50% communication overhead than update-on-finish approach while sustaining better load balancing performance than periodic mechanisms in related work.