• Journal of the Korea Furniture Society
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• v.21 no.3
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• pp.261-272
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• 2010

The aim of the present study was to investigate the relations between wooden toy and development of infant and young children by taking only the commercialized wooden furniture which would be suitable for the developmental area for infant and young children, among the physical environment influencing the balanced development and development for them. The recommended standard for them was the commercialized good and the only advanced toys for the development of infant and young children was primary selected, in case of different furniture for same purpose with regardless of manufacturer, country of origin and price. The selected wooden toys for development of infant and young children covered the following test conditions. They keep the soft and clean surfaces and the corners are the round-finished so safe. The dyeing and coloring are so clear like the rainbow-colored in compliance with the international safety norm, and the paint material used are harmless to the people, because they have already passed the European Safety Norm EN 71 which is the most authoritative and strict standard in the world and contained accordingly little heavy metals, toxic substances and also allergy pigment under the maximum permissible standard. The size of wooden toys are not small enough for infant and young children to be able to swallow and this is important check point, because infants tend to feel the object in their own touching and therefore to have everything to the lip. The paint used was the toys-oriented goods and proved by the test regarding saliva and sweat.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.628-649
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• 2017

Security and resource-saving are both demands of the fifth generation (5G) wireless networks. In this paper, we study the secrecy spectrum efficiency (SSE) and secrecy energy efficiency (SEE) of a K-tier massive multiple-input multiple-output (MIMO) enabled heterogeneous cellular network (HetNet), in which artificial noise (AN) are employed for secrecy enhancement. Assuming (i) independent Poisson point process model for the locations of base stations (BSs) of each tier as well as that of eavesdroppers, (ii) zero-forcing precoding at the macrocell BSs (MBSs), and (iii) maximum average received power-based cell selection, the tractable lower bound expressions for SSE and SEE of massive MIMO enabled HetNets are derived. Then, the influences on secrecy oriented spectrum and energy efficiency performance caused by the power allocation for AN, transmit antenna number, number of users served by each MBS, and eavesdropper density are analyzed respectively. Moreover, the analysis accuracy is verified by Monte Carlo simulations.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.39-42
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• 1994

The application of speed or position control technique in AC drives demands accurate position and velocity feedback information. Generally, resolver and absolute encoders are used as a velocity or position sensor. But they increase cost and when the sampling frequency is faster than sensoer's output frequency we can't Set exact information. In order to solve this problem this thesis proposes a speed and a position observer design for Permanent-Magnet Synchronous Motors(PMSM) specialty in low speed drives. Most literatures on this topic design the observer based on the field_oriented d_q model. But in this thesis, a new approach to machine dynamics is proposed. Since it is difficult to design the observer using the nonlinear model, the machine model is here linearlized at the operating point. The observer designed is implemented by software using Intel's 8097 microprocessor and verifies the proper performance of observer by simulation and experiment.

• The Research Journal of the Costume Culture
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• v.16 no.3
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• pp.547-558
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• 2008

This study aims on observing the social recognition and its aspects for men taking care of their outer appearances at current point where men are rapidly rising as the main consumer in the beauty industry while their interest for outer appearances are increasing. Therefore, we observed the overall trend and changes in social recognition for male looks by analyzing the contents of newspaper articles from 1990 to 2005 that play the critical role of spreading new information trend while reflecting the interest of people of a certain era. As a result, articles related to male looks were divided into fashion, hair, skin and cosmetics, physical image, cosmetic surgery, trend related to male looks, and male oriented stores and sites, and among them, articles related to fashion and skin took up the highest ratio. Especially articles related to the trend took up the largest ratio as it reflects the properties of two industries launching new products. Moreover, articles related to male looks tended to increase generally according to timely changes, and rapidly increased especially since 2000.

• Journal of Agricultural Extension & Community Development
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• v.10 no.2
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• pp.229-237
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• 2003

Since the 1960s in Korea, major broadcasting channels broadcasted farm television programs, however, airing of these programs were reduced in the 1990s. This was due to the declining number of farmers, and the low popularity rating of farm television programs. To cope with the situation, agriculture businessmen, farmers, and the officials concerned tried to acquire the independent farming television channel in cable television and satellite television, In 1998, one cable television channel started broadcasting, while another channel in satellite television began its broadcasting in 2001. One of the major concerns of the people in the broadcasting was actualization of the public interests in the new media multi-channel age. Recognizing this point, the study explored a few areas of concern such as conceptualizations of the public interest of the people in the digital age, examination of the surroundings of program production and marketing, and survey the media use behavior of target audience - rural residents; In the concept of the public interest, there are two points of view; market focused and democratic principle oriented. As the digitalization of broadcast advances and the logic of economics prevails, it is difficult to offer the public broadcasting service to farmers, however, democratic principles should be more emphasized. The rural resident prefer major terrestrial television channel to cable television and satellite television channel, and in media use behavior, the medium of major terrestrial television would be more useful for farm broadcasting.

• Journal of Korean Port Research
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• v.13 no.2
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• pp.267-278
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• 1999

Since the mid 1980s, the concept of logistics has become more important to the enterprises in strategic sense because it had aggrandized itself to more comprehensive and integrative concept. Therefore study on the service organization of the logistics system for customer’s satisfaction from the management’s point has been focused as one of the major subject in order to improve the logistics quality which would ultimately increase the value of logistics service. This study has been focused on what the port logistics functions and the factors of the port logistics quality are those Korean port managers acknowledge as important factor. And examins these port logistics quality levels and the port logistics value (port productivity, service results) obtained by the results of these activities while reviewing the relation of the custom value which the port managers evaluate in order to evaluate and promote the competitiveness of the Korean port. According to the study results the port logistics function which the Pusan Container Terminal managers recognized as important were customer service management the flexibility of the port facilities and curtailment of the original operation cost of the port. It also indicated that the managers recognized the importance of the customer-oriented terminal management as it showed a close relationship with the port quality level.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.4
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• pp.206-213
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• 2012

This paper propose a improved speed control system for five-phase squirrel-cage induction motor(IM) considering effects of 3rd. harmonic current components with field oriented control(FOC) A five-phase IM drives present unique characteristics due to the additional degrees of freedom and also drives possess many others advantage compared with the traditional three-phase motor drive system, such as reducing a amplitude of torque pulsation at low frequency and increasing the reliability. In order to maximize the torque per ampere, the proposed motor has concentrated windings. The produced back-electromotive force is almost trapezoidal, and the motor is supplied with the combined sinusoidal plus third harmonic of currents. There is necessary to controlled 3rd harmonic current. For presenting the superior performance of the proposed the speed control system, experimental results are presented using a 32-bit fixed point TMS320F2812 DSP with 1.5[KW] induction motor.

• Earthquakes and Structures
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• v.7 no.5
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• pp.647-665
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• 2014

Squat reinforced concrete walls require enough shear strength in order to promote flexural yielding, which creates the need for designers of an accurate method for strength prediction. In many cases, especially for existing buildings, strength estimates might be insufficient when more accurate analyses are needed, such as pushover analysis. In this case, estimates of load versus displacement are required for building modeling. A model is developed that predicts the shear load versus shear deformation of squat reinforced concrete walls by means of a panel formulation. In order to provide a simple, design-oriented tool, the formulation considers the wall as a single element, which presents an average strain and stress field for the entire wall. Simple material constitutive laws for concrete and steel are used. The developed models can be divided into two categories: (i) rotating-angle and (ii) fixed-angle models. In the first case, the principal stress/strain direction rotates for each drift increment. This situation is addressed by prescribing the average normal strain of the panel. The formation of a crack, which can be interpreted as a fixed principal strain direction is imposed on the second formulation via calibration of the principal stress/strain direction obtained from the rotating-angle model at a cracking stage. Two alternatives are selected for the cracking point: fcr and 0.5fcr (post-peak). In terms of shear capacity, the model results are compared with an experimental database indicating that the fixed-angle models yield good results. The overall response (load-displacement) is also reasonable well predicted for specimens with diagonal compression failure.

• Journal of the Korea Society of Computer and Information
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• v.12 no.4
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• pp.103-110
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• 2007

Ubiquitous computing is a vogue word, and its service is very popular in Korea. However, present ubiquitous service(u-Service) is thought to be more oriented to the provider's point of view, not the consumer's. To complement this problem, an online survey was performed for internet users, which consists of 24 single choice questions on six fields such as transportation, healthcare, environment/city-management, culture/education, administration, and industry. 2463 people joined the survey, who were grouped according to their age, resident region, level of education, and sex. Each group's demand for specific field of u-Service was examined. General level of demand was higher in case of the elderly and male than the younger and female for overall u-Service.

• Journal of Magnetics
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• v.21 no.2
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• pp.209-214
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• 2016

This paper analyzes the magnetic property according to the machined shape of steel material with non-oriented silicon steel (50PN470/50A470), that is most commonly used in the design of electrical equipment. Toward this end, specimens were produced and divided into Bar-Specimen (Epstein Frame Tester) and Ring-Specimen (Toroidal Ring Tester). The characteristics of the electrical Silicon steel were measured using the instruments solely dedicated to measuring each specimen. The core loss of the Bar-Specimen, which is commonly used, was found to be less than that of the Ring-Specimen. This is a very important design factor in achieving the objectives of improving the product efficiency and predicting the performance of electrical equipment. It serves as a critical point of view in order to reduce the error between design value and product value. A comparative analysis was conducted regarding various characteristics (Hysteresis, B-H characteristic, Iron loss, Minor loop, Coercive force, Residual magnetic flux density, etc.) of the electrical silicon steel considered in the design of the electrical equipment according to the specimen.