• KDI Journal of Economic Policy
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• v.34 no.4
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• pp.117-156
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• 2012

This paper decomposes and estimates trend/cyclical components of some key macro variables-GDP, inflation, and interest rate, using a simple DSGE model along with flexible trend specification. The extracted cyclical components of output and interest rate are similar to HP-filtered counterparts, despite some differences in persistence and volatility, while inflation resembles that from BK filtering. This implies that the usual practice of applying a single filtering method to the data of interest may be problematic. When the baseline model is extended to incorporate consumption habit and price indexation, habit turns out to be important in explaining the persistence of business cycles. Comparison of several alternative models shows that the usual practice of estimation of DSGE model using filtered data leads to biased results. Finally, various sensitivity analyses illustrate that (1) allowing for correlation between structural cyclical shocks and trend shocks and (2) including irregular components (in inflation rate) may deliver interesting/important implication for gap estimates.

• Journal of The Korean Association of Information Education
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• v.11 no.3
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• pp.339-347
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• 2007

Along with developments of information and communication technologies, internet has spread not only all over the society, but also our everyday life deeply. Recently, requirements for e-learning using internet in the educational aspect have a great influence on the changes of school educations. Cyber Home Learning System, in particular, has been implemented throughout the nation for the purpose of reducing private expenditure for education and promoting substantial improvements in quality of public education. However, there have been exposed many problems with respect to quality of operations and managements of the system comparing to its quantitative growth, and so, at this point in time, researcher conducted analysis of actuality of perceptions of both elementary and middle school teachers with a focus on the case of S System in K province. To test this, total 278 participants were sampled from the elementary schools (139 teachers) and the middle schools (139 teachers) located in K province and were asked to complete a survey and the results therefrom were analyzed accordingly. Results from the analyses revealed that elementary school teachers responded more positively than other respondents in the most areas, including supply of a variety of learning contents of S System, quality of contents, and providing for helps insomuch as to complement school works, etcetera. In addition, researcher has found out that, to make the system become all the more efficient, it shall be required to establish a strategy in order to induce students' interest in the system, as well as to construct infrastructure for facilitating the use of computer. And that there are also needs for continuous supports from both the school and the education authority concerned, and for method of flexible operation of curriculum.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.7
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• pp.479-490
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• 2014

A lower extremity exoskeleton is a robot device that attaches to the lower limbs of the human body to augment or assist with the walking ability of the wearer. In order to improve the wearer's walking ability, the robot senses the wearer's walking locomotion and classifies it into a gait-phase state, after which it drives the appropriate robot motions for each state using its actuators. This paper presents a method by which the robot senses the wearer's locomotion along with a novel classification algorithm which classifies the sensed data as a gait-phase state. The robot determines its control mode using this gait-phase information. If erroneous information is delivered, the robot will fail to improve the walking ability or will bring some discomfort to the wearer. Therefore, it is necessary for the algorithm constantly to classify the correct gait-phase information. However, our device for sensing a human's locomotion has very sensitive characteristics sufficient for it to detect small movements. With only simple logic like a threshold-based classification, it is difficult to deliver the correct information continually. In order to overcome this and provide correct information in a timely manner, a probabilistic gait-phase classification algorithm is proposed. Experimental results demonstrate that the proposed algorithm offers excellent accuracy.

• Journal of the Korea Convergence Society
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• v.11 no.7
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• pp.281-287
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• 2020

The purpose of this study is to examine whether the effect of service satisfaction regarding the accessibility of child care services varies between dual-earner and single-earner families. In particular, we conducted the analysis by dividing the service accessibility into sub-areas. The study sample consisted of 267 parents living in Seoul and Gyeonggi region. As a result of the analysis, accommodation in use time and affordability influenced satisfaction in the single-earner families, and information acquisition and acceptability in the dual-earner families. For single-earner families, the more convenient the use time of the childcare institution and the less the service cost burden, the higher the satisfaction. The dual-earner families had higher satisfaction levels if it was easier to obtain information about the childcare centers and weaker the religious characteristics of the childcare centers. Based on the research results, it is necessary to differentiate the burden of cost and provide more flexible operation of childcare service operating hours. In addition, it is necessary to devise a policy method to increase the transparency of information to childcare institutions.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.3
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• pp.164-173
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• 2014

In underwater robotics, vision would be a key element for recognition in underwater environments. However, due to turbidity an underwater optical camera is rarely available. An underwater imaging sonar, as an alternative, delivers low quality sonar images which are not stable and accurate enough to find out natural objects by image processing. For this, artificial landmarks based on the characteristics of ultrasonic waves and their recognition method by a shape matrix transformation were proposed and were proven in Part 1. But, this is not working properly in undulating and dynamically noisy sea-bottom. To solve this, we propose a framework providing a selection phase of likelihood candidates, a selection phase for final candidates, recognition phase and tracking phase in sequence images, where a particle filter based selection mechanism to eliminate fake candidates and a mean shift based tracking algorithm are also proposed. All 4 steps are running in parallel and real-time processing. The proposed framework is flexible to add and to modify internal algorithms. A pool test and sea trial are carried out to prove the performance, and detail analysis of experimental results are done. Information is obtained from tracking phase such as relative distance, bearing will be expected to be used for control and navigation of underwater robots.

• Journal of Broadcast Engineering
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• v.14 no.6
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• pp.796-806
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• 2009

SVC (Scalable Video Coding) is a new video coding standard to provide convergence media service in heterogeneous environments with different networks and diverse terminals through spatial-temporal-quality combined flexible scalabilities. This paper presents the performance analysis on packet loss in the delivery of SVC over IP networks and an efficient adaptation method to packet loss caused by buffer overflow. In particular, SVC with MGS (Medium Grained Scalability) as well as spatial and temporal scalabilities is addressed in the consideration of packet-based adaptation since finer adaptation is possible with a sufficient numbers of quality layers in MGS. The effect on spatio-temporal quality due to the packet loss of SVC with MGS is evaluated. In order to minimize quality degradation resulted by packet loss, the proposed adaptation of MGS based SVC first sets adaptation unit of AU (Access Unit) or GOP corresponding to allowed delay and then selectively discards packets in order of importance in terms of layer dependency. In the experiment, the effects of packet loss on quantitative qualities are analyzed and the effectiveness of the proposed adaptation to packet loss is shown.

• Journal of the Korean Society of Costume
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• v.25
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• pp.249-268
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• 1995

Parody has recently prevailed as one of the important techniques of creation in art. The purposes of this study are to reaffirm the pos-ition of fashion as an art by clarifying parody depicted in fashion and to make an opportunity to reconsider the meaning of creation in fashion design through the significance of par-ody. For these purposes, documentary studies about parody in literature and art which had been discussed more often were preceded as a framework of this research. framework of this research. Basedd upon that, parody phenomena in fashion as well as art were analyzed. The synthetic results are as follows ; 1. Parody is a kind or critical technique and can be conceived as a process of creation. The established primary style (material) which is well-known and familiar is imitated and then is recreated in new manner through the three types of parodization, that is, the change of its external form, the change of its internal mean-ing and the shift from its place (i.e. displace-ment). 2. Parody in fashion is also analyzed based upon the three types of parodization which designer's will and expression is necessarily required. First, the parody through the change of external form is to have its effect of novelty, unexpectedness, playfulness, wit, mackery, satire, irony, paradox by changing the form of the original through imitation with similarity, transformation, exaggeration, em-phasis. Second, the parody through the change of internal meaning is to bring about paradox, irony, contempt, satire, unex-pectedness by applying the original to inappro-priate subject through its substitution, inver-sion. Third, the parody through displacement is to pursue a jarring incongruity that results from shifting the original to other context. Its effect consists of paradox, unexpectedness, playfulness, ridicule, mockery, satire, irony. In general, the parody technique in fashion can be used to have an intention of expressing seriousness, playfulness, satire, grotesque. The representative designers using the parody technique are Lagerfeld, Ricci, YSL, Yama-moto, Castelbajac, Gaultier, Mugler, West-sood, Steiner and so on. 3. Parody is the technique which imitates and then recreates the preceding style ; is at the same time the method which challenges the existing concept of originality-singleness and uniqueness. It reflects the more flexible concept of modern creation in art as well as fashion. The imitation as the creation, the characteristic of parody is recognized as an creative expressiveness, publicity, intention. Thus it differenciates from copy which is uncritical mimicry.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.2
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• pp.52-59
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• 2008

The objective of this study is to develop an automatic object changer unit to improve processing problems existed in the conventional horizontal machining center. To achieve this goal, this study designed a horizontal transfer as the second project continued to the first project that designed a upward and downward traverse unit. A horizontal traverse unit shows a symmetric structure and consists of frame, which consists of four unit tools, motor and reducer, which are fixed at a frame, operation unit with pinions, first traverse unit, and second traverse unit. Constraint conditions based on the operation mechanism with these elements were configured and obtained following results after modeling a model for a traverse motor. In the kinematic expression of sliding motion with one degree of freedom, the sliding motion is constrained. Also, the rack 3 installed at a frame is used to configure possible kinematic constraint conditions of the rack 2 according to the rolling motion of the pinion 2 in the first traverse unit. In addition, the moment of inertia that is a type of kinetic energy in a converted horizontal traverse unit in the side of the reducer can be applied to introduce the moment of inertia of a converted horizontal traverse unit in the side of the reducer by using the sum of kinetic energy in the rack and pinion, which is a part of the horizontal traverse unit. Also, the equation of motion of the converted upward and downward traverse unit in the side of the motor using the equation of motion of the motor. Furthermore, the horizontal traverse unit predetermines the mass of the first and second traverse unit and applied load including the radius and reduction ratio of the pitch circle in the pinion 1 and applied load to the rack 2. Then, a proper motor can be determined using several parameters in the upward and downward traverse unit in order to verify such predetermined specifications. In future studies later this study, a simulation that verifies the results of the previous two stages of studies using a finite element method.

• Journal of Korean Society of Transportation
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• v.35 no.4
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• pp.348-359
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• 2017

Recently, various public transportation activation policies are being implemented in order to mitigate traffic congestion in metropolitan areas. Especially in the metropolitan area, the bus information system has been introduced to provide information on the current location of the bus and the estimated arrival time. However, it is difficult to predict the travel time due to repetitive traffic congestion in buses passing through complex urban areas due to repetitive traffic congestion and bus bunching. The previous bus travel time study has difficulties in providing information on route travel time of bus users and information on long-term travel time due to short-term travel time prediction based on the data-driven method. In this study, the path based long-term bus travel time prediction methodology is studied. For this purpose, the training data is composed of 2015 bus travel information and the 2016 data are composed of verification data. We analyze bus travel information and factors affecting bus travel time were classified into departure time, day of week, and weather factors. These factors were used into clusters with similar patterns using self organizing map. Based on the derived clusters, the reference table for bus travel time by day and departure time for sunny and rainy days were constructed. The accuracy of bus travel time derived from this study was verified using the verification data. It is expected that the prediction algorithm of this paper could overcome the limitation of the existing intuitive and empirical approach, and it is possible to improve bus user satisfaction and to establish flexible public transportation policy by improving prediction accuracy.

• Journal of Korea Soil Environment Society
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• v.1 no.1
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• pp.89-102
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• 1996

An integrated model is presented to describe underground flow and mass transport, using a multicomponent multiphase approach. The comprehensive governing equation is derived considering mass and force balances of chemical species over four phases(water, oil, air, and soil) in a schematic elementary volume. Compact and systemati notations of relevant variables and equations are introduced to facilitate the inclusion of complex migration and transformation processes, and variable spatial dimensions. The resulting nonlinear system is solved by a multidimensional finite element code. The developed code with dynamic array allocation, is sufficiently flexible to work across a wide spectrum of computers, including an IBM ES 9000/900 vector facility, SP2 cluster machine, Unix workstations and PCs, for one-, two and three-dimensional problems. To reduce the computation time and storage requirements, the system equations are decoupled and solved using a banded global matrix solver, with the vector and parallel processing on the IBM 9000. To avoide the numerical oscillations of the nonlinear problems in the case of convective dominant transport, the techniques of upstream weighting, mass lumping, and elementary-wise parameter evaluation are applied. The instability and convergence criteria of the nonlinear problems are studied for the one-dimensional analogue of FEM and FDM. Modeling capacity is presented in the simulation of three dimensional composite multiphase TCE migration. Comprehesive simulation feature of the code is presented in a companion paper of this issue for the specific groundwater or flow and contamination problems.