• Korean Journal of Child Studies
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• v.18 no.1
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• pp.5-21
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• 1997

This study compared children's daily activities In the preschools of middle-and lower-income communities. 22 children, evenly divided by community and children's gender, were observed for 3 hours on 5 consecutive days. The observers followed the target child, gathering data during 30-second "windows" every 4 1/2 minutes. A total of 750 observations were used in the analyses. The findings show the variation in children's activities as a function of community differences. In the case of academic activities, children of middle-income community were more exposed to and engaged in play with academic objects more than children of the of low-income community. A reverse tendency, however, was found in academic lessons. Children of low-income community were more exposed to work than their counterparts. Children of middle-income community were engaged in child-adult conversation more than those of low-income community. In addition, children of the middle-income community initiated their involvement in play and conversation more than their counterparts, though no difference was found in children's initiation of activities.

• Journal of the Optical Society of Korea
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• v.1 no.1
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• pp.48-51
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• 1997

A quantum well electroabsorption waveguide modulator utilizing a field-induced refractive index change was designed and fabricated. The on/off ratios of the device were investigated as a function of wavelength over the spectral range of 850 nm to 910 nm for the various reverse biases. The field-induced refractive index variations associated with quantum-confined Stark effect was theoretically obtained based on the measured on/off ratios. The resulting maximum refractive index change(${\DELTA}n) of ~7.5 {\times} 10^{-4}$ at -8 V was estimated.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.69-74
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• 2007

The source mechanism parameters of the Ulgin earthquake on 29 May 2004 are analyser using moment tensor inversion technique. The Green's function are calculated for the Kim's(1985) crust model of southern Korean Peninsula. Results derived from the Ulgin earthquake show the dependence of azimuthal station distribution and epicentral distances. final results show fairly good agreement to those of other authors. the focal mechanism for the Ulgin earthquake is found to be oblique reverse motion with NNE strike. The focal depth is estimated to be 10-12km.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.578-580
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• 2005

This paper proposes the algorithm for the initial pole-position estimation of a surface PM-LSM, which is carried out under the pseudo-position control with-out a pole sensor and is insensitive to the motor parameters. This algorithm is based on the principle that the initial pole-position is calculated by the reverse trigonometric-function using the two reference currents, which are informed from the speed controller. The effectiveness of the proposed algorithm is confirmed by the arithmetical analysis and the experiment. IPP is well estimated within a satisfied moving-distance and a shorter estimation taken-time even if large disturbance such as cogging and friction are existed.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.549-551
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• 2005

Bidirectional DC/DC converters allows transfer of power between two dc sources, in either direction. Due to their ability to reverse the direction of flow of power, they are being increasingly used in many applications such as battery charger/dischargers, dc uninterruptible power supplies, electrical vehicle motor drives, aerospace power systems, telecom power supplies, etc. This paper proposes a new bidirectional Sepic/zeta converter. It has low swicthing loss and low conduction loss due to auxiliary communicated circuit and synchronous rectifier operation, respectively. Because of positive and buck/boost-like DC voltage transfer function(M=D/1-D), the proposed converter is very desirable for use in distributed power system . The proposed converter also has both transformerless version and transformer one.

• Archives of Craniofacial Surgery
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• v.18 no.4
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• pp.264-268
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• 2017

The zygomaticomaxillary complex (ZMC) functions as a buttress for the face and is the cornerstone to a person's aesthetic appearance, by both setting the midfacial width and providing prominence to the cheek. Malar deficiency is often acquired by blunt injury incurred in a traumatic accident, resulting in ZMC fracture. A 48-year-old male patient presented a right ZMC fracture after contusion injury by a baseball. He only received conservative management and later he suffered discomfort during mouth opening at the moment of mastication, due to trismus involving the temporomandibular joint. In the current case, we describe a surgical technique, by which the malar body is shifted anteriorly and laterally after combined oblique-vertical osteotomy. The technique presented, eventually restored the former aesthetic position of the malar complex and symmetry, and, moreover, improved mastication function.

• The Transactions of the Korea Information Processing Society
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• v.7 no.3
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• pp.818-830
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• 2000

Automation tools for program analysis are needed in order to program understand and maintain, extract the characteristics of object-oriented program such as class name, member function and data member. In this paper, we carried out design and implementation of the automation tool for effective maintenance of object-oriented software. Being based on Reverse Engineering, this approach extracts class relationship information from C++ source code and generates object-oriented model of class diagram using UML as the standard object-oriented methodology. Therefore, this paper provides developers visualized including class information, definitions of classes, inheritance relationships, set relationships, and simple reference relationships. Finally in this paper, we propose a method that construct class relationship information to table in analysis state and make form of table construction to link form so tat developers can perform understanding and maintaining program efficiently. And this method enable to restructure and reuse in object-oriented model.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.2
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• pp.71-76
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• 2017

In this study, we learned about the emergence of on-line communications originating from peoseuteol Computer Communications, the limitations of online communication, and the definition, traits and development of emoticons that serve as complementary roles, such as emotion and status. After analyzing various literacture and references, it was found that the emoticons functioned as a function of communicating the visual language of the digital era and communicating more sensitively to emotional factors. In a multimedia environment, emoticons are developed at a more advanced stage as the users' own icons due to a stronger tendency to pursue particularity and uniqueness. It is expected that eomotions added with multimedia functions will be more popular and vary in type. However, although the diversification of emotions as a commercial tool is already actively progressing, there appears a reverse effect in which an excessive use of emoticons is considered insincere in online communications. In such a background, research should be conducted that can support a systematic and effective development of emoticons through visual research rather than producing multimedia emoticons indiscreetly.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.10
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• pp.1321-1327
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• 2014

Faulted section identification is one of the most important function in distribution automation systems. Conventional over current detection based fault indicators frequently mal-operate due to the reverse fault current from the renewable energy resources. This paper present a new faulted section identification method based on the fuzzy decision making technique. In order to establish feasibility of the proposed method, case studies using Matlab Simulink has been performed.

• Journal of Korean Institute of Industrial Engineers
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• v.33 no.3
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• pp.312-321
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• 2007

We address a disposal issue of returned products in a product recovery system where a single product is stocked in order to meet a demand from customers who may return products after usage. Product returns occur randomly and can be accepted for remanufacturing or disposed of depending on the state of the system. We examine the structure of the optimal disposal policy for returned product that utilizes the information of the inventory of both serviceable and remanufacturable products. Numerical study indicates that it can be characterized by a monotonic threshold type of the curve. A disposal is allowed only when the remanufacturable inventory level exceeds a threshold which is the function of the inventory level of serviceable product and it is decreasing as the serviceable inventory level increases. Sensitivity analysis also indicates that the optimal disposal policy and the optimal profit have monotonic properties with respect to system parameters.