• Journal of Communications and Networks
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• v.5 no.1
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• pp.65-72
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• 2003

Internet roundtrip delay/time (RTT) prediction plays an important role in detecting packet losses in reliable transport protocols for traditional web applications and determining proper transmission rates in many rate-based TCP-friendly protocols for Internet-based real-time applications. The widely adopted autoregressive and moving average (ARMA) model with fixed-parameters is shown to be insufficient for all scenarios due to its intrinsic limitation that it filters out all high-frequency components of RTT dynamics. In this paper, we introduce a novel parameter-varying RTT model for Internet roundtrip time prediction based on the information theory and the maximum entropy principle (MEP). Since the coefficients of the proposed RTT model are updated dynamically, the model is adaptive and it tracks RTT dynamics rapidly. The results of our experiments show that the MEP algorithm works better than the ARMA method in both RTT prediction and RTO estimation.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.1-6
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• 1992

A principle of "orthogonalization" is proposed as an extended notion of hybrid (force and position) control for robot manipulators under geometric endpoint constraints. The principle realizes the hybrid control in a strict sense by letting position and velocity feedback signals be orthogonal in joint space to the contact force vector whose components are exerted at corresponding joints. This orthogonalization is executed via a projection matrix computed in real-time from a gradient of the equation of the surface in joint coordinates and hence both projected position and velocity feedback signals become perpendicular to the force vector that is normal to the surface at the contact point in joint space. To show the important role of the principle in control of robot manipulators, three basic problems are analyzed, the first is a hybrid trajectory tracking problem by means of a "modified hybrid computed torque method", the second is a model-based adaptive control problem for robot manipulators under geometric endpoint constraints, and the third is an iterative learning control problem. It is shown that the passivity of residual error dynamics of robots follows from the orthogonalization principle and it plays a crucial role in convergence properties of both positional and force error signals.force error signals.

• Journal of Environmental Impact Assessment
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• v.13 no.4
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• pp.213-222
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• 2004

Exergy is defined as the amount of work (entropy-free energy) a system can perform when it is brought into thermodynamic equilibrium with its environment. Exergy measures the distance from the inorganic soup in energy terms. Therefore, exergy can be considered as fuel for any system that converts energy and matter in a metabolic process. The aim of this study is to introduce structural dynamic modelling which is based on maximum exergy principle. Especially, almost ecological models couldn't explain algal succession until now. New model (structural dynamic model) is anticipated to predict or explain the succession theory. If the new concept using maximum exergy principle is used, algal succession can be explained in many actual cases. Therefore, It is estimated that structural dynamic model using maximum exergy principle might be a excellent tool to understand succession of nature from now on.

• Proceedings of the Safety Management and Science Conference
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• 2008.04a
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• pp.443-450
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• 2008

This paper is to present design principle and operation strategy of acceptance control chart by the use of OC-Based sampling inspection for continuous data. The unified control limits for acceptance control chart when considering both APL(Acceptable Process Level) and RPL(Rejectable Process Level) are proposed. The control limits can be also extended to the acceptance control chart with unknown process standard deviation.

• Journal of Korean Public Health Nursing
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• v.15 no.1
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• pp.27-41
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• 2001

The purpose of this study was to discern the level of satisfaction of postpartum care in hospitals. the level of importance of traditional postpartum care and the need for home health care for postpartum women. The study's design was to obtain data needed to develop a community-based postpartum care program and to improve the quality of nursing for postpartum care recipients. Data for the study was collected from 1 March to 31 June 2000 from 116 postpartum care recipients treated in Chung-Buk, Korea. Data analysis consisted of frequency, percentage, t-test, and ANOVA. using SPSS win program. The results the of analysis were as follows: 1) The level of satisfaction of postpartum care in the hospital (mean 1.31) was very low. The most laudable items of nursing care by category were: moderate satisfaction with 'perineal wound care' (2.04) and 'afterpain observation'(2.09). The overall level of satisfaction of postpartum care in the hospital. however, was very low. 2) Among other items of postpartum care in the hospital, 'postpartum exercise' $(25.9\%)$. 'assessment and support for postpartum depression' $(25.9\%)$, 'operation wound care for women who underwent Caesarean sections' $(24.5\%)$. and 'contraception and family planning' $(20.4\%)$ showed a need for home health care for postpartum care recipients above $20\%$. 3) The level of importance of traditional postpartum care (Sanhujori) was relatively high (mean 2.72). The importance of Sanhujori by category was as followed: 'the fourth principle: protecting the body from harmful strains' was the highest (2.88), 'the third principle: eating well', 'the first principle: invigorating the body by augmenting heat and avoiding cold', 'the second principle: resting without working', 'the fifth principle: keeping clean' and 'the sixth principle: handling with the whole heart' showed 2.85, 2.80, 2.70, 2.51 and 2.46 respectively. 4) The need for home health care with Sanhujori was very low. 5) The relationship between demographic factors and the level of satisfaction with postpartum care in the hospital was as follows: the satisfaction levels were significantly different among' delivery frequency' and 'health status' alteration after delivery'. 6) The relationship between demographic factors and the importance of the Sanhujori category was as follows: There were no significant differences in the level of importance of the first and the forth principle of Sanhujori. The level of importance of the second principle of Sanhujori was significantly different among 'income' and 'family type'. The level of importance of the third principle of Sanhujori was significantly different among 'having a boy'. The level of importance of the fifth principle of Sanhujori was significantly different among 'income' and 'feeding type'. The level of importance of the sixth principle of Sanhujori was significantly different among 'education background' and 'feeding type'. In conclusion. the findings of this study illustrate the nursing needs of postpartum care recipients. It provides a challenge to caregivers in the healthcare industry to develop a continuous postpartum care program and integrative postpartum care system that embodies the oriental and western paradigm for the promotion of women's health.

• Bulletin of the Korean Mathematical Society
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• v.50 no.5
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• pp.1539-1554
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• 2013

In this paper, we extend Donsker's invariance principle to the case of random partial sums processes based on a double sequence of row-wise i.i.d. random variables.

• Journal of the Korean Institute of Telematics and Electronics
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• v.11 no.3
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• pp.27-31
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• 1974

The maximum principle of Pontryagin provides the celebrated method to obtain the optimum control switching time and switching points on the nuclear reactor. The control trajectories transfered from its initial state to the target state are optimized based on time optioptimal control method with the given reactor parameters and the piecewise constant input values.

• Communications of Mathematical Education
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• v.23 no.1
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• pp.85-108
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• 2009

The purposes of the study were to develop instructional materials based on Freudenthal's guided reinvention principle for teaching proofs and to investigate how the teaching method based on guided reinvention principle affects on 8th grade students' ability to write proofs and learning attitude toward proofs. Teaching based on guided reinvention principle placed emphasis on providing students opportunities to make a mathematical statement and prove the statement by themselves throughout various activities such as exploring, conjecturing, and testing the conjectures. The study found that students who studied proving with instructional materials developed by guided reinvention principle showed statistically higher mean scores on the posttest than students who studied by a traditional teaching method depending onteacher's explanation. Especially, on the posttest item which requested to prove a whole statement without presenting a picture corresponding to the statement, a big difference among students' responses was found. Many more students in the traditional group did not provide any response on the item. According to the results of the questionnaire regarding students' learning attitudes, the group who studied proving by guided reinvention principle indicated relatively more positive attitudes toward learning proofs than the counterparts.

• International Journal of Highway Engineering
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• v.14 no.5
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• pp.75-83
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• 2012

PURPOSES: Suggestion of asphalt binder constitutive model based on time-temperature superposition principle and overstress concept in order to describe behavior of asphalt binders. METHODS: A series of temperature sweep tests and multiple stress creep and recovery(MSCR) tests are performed to verify the applicability of time-temperature superposition principle(t-Ts) and to develop viscoelastoplastic constitutive equation based on overstress concept. For the tests, temperature sweep tests at various high temperature and various frequency and MSCR test at $58^{\circ}C$, $64^{\circ}C$ $70^{\circ}C$, $76^{\circ}C$, and $82^{\circ}C$ are performed. From the temperature sweep tests, dynamic shear modulus mastercurve and time-temperature shift function are built and the shift function and MSCR at $58^{\circ}C$ are utilized to determine model coefficients of VBO model. RESULTS: It is observed that the time-temperature shift function built at low strain level of 0.1% is applicable not only to 1.0% strain level temperature sweep test but also maximum 500,00% strain level of MSCR test. As well, the modified VBO model shows perfect prediction on MSCR measured strain at the other temperatures. CONCLUSIONS: The Time-temperature superposition principle stands hold from very low strain level to very high strain level and that the modified VBO model can be applicable for various range of strain and temperature region to predict elastic, viscoelastic, and viscoplastic strain of asphalt binders.

• Journal of the Korean Institute of Rural Architecture
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• v.18 no.2
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• pp.47-54
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• 2016

The objective of this study is to propose the principle and method of the spatial system modification for the compatibility of habitability and tourism convenience in cultural property villages. Based on the field survey on tourists' routes, activities and their durations in Oeam-maeul, the problems of conflict, between habitability/residents and tourism/tourists, and their causes are analyzed. And the modification principle and method of spatial system is proposed as follows; The basic principle of the spatial system modification is to respect the traditional hierarchy in village roads, between the main road and sub-roads, and the territoriality of settlement space that is typically differentiated as the social, individual, and ceremonial domains, from the front to rear part of settlement. With this principle, it is recommended to restrict the tour route to one that is composed of the main road and the periphery road of housing area, and some connecting sub-roads. based on the surveyed tourists's routes. And it is suggested that the tourist facilities, whether they are existing houses or newly built buildings, and the tourist programs are necessary for experience tourism to cultural property villages, and they are proposed to be placed along the restricted tour route.