• Journal of the Korean Society for Library and Information Science
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• v.46 no.4
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• pp.341-360
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• 2012

This study is part of a larger project that investigated the patterns of children's use of educational graphic novels (EGNs), a publication format that has been popular among young readers in Korea since 2000. In-depth interviews with elementary school teachers and school librarians uncovered tension and gaps between these adult professionals and children's enjoyment of the format. Interviewees' views on EGNs ranged from limited tolerance to a potential candidate for high-interest / low-vocabulary reading. All teachers and school librarians urged for guidelines and criteria for selecting and evaluating EGNs for children.

• Tribology and Lubricants
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• v.31 no.4
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• pp.170-176
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• 2015

As a continuation of Part I, which developed a design formula of the minimum corner radius (R_min) for restraining tribological failures, Part II investigates design parameters such as material properties and contact force. As design examples, Al 7075-T651, SST 304 and HT-9 are chosen for the materials and 1, 10 and 100 kN are used for the forces. The results show that the difference in R_min decreases as either the elastic modulus increases or the contact force decreases. Given the same material and force, the permissible R_min decreases as the flat region increases and vice versa. Because the R_min values obtained from the examples are very small, the dimensions of the corner radius normally designed in engineering structures are regarded acceptable. The von Mises stress evaluated for a typical example, which is far below the yield strength, confirms this interpretation. Nevertheless, the present work can provide a design criterion as well as a guideline for quality control in the manufacturing of, in particular, contact corners, which has not been attempted before to the best of the author’s knowledge. In addition, this paper considers the problem of a step that may be formed in the contact contour by using a similar approach. The result shows that no size of the step is permissible.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.402-403
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• 2014

Damping of multi-span tube with loose supports according to the finite support clearances is investigated through the experimental modal analysis. Loose intermediate support leads to strong nonlinearity in tube dynamics, provides statistical nature, and increases tube damping through impacting and friction at the supports. Fraction of critical damping was estimated by the modal curve fitting to parameter estimation from the measured frequency response functions. Magnitude of random excitation force, which can reproduce the in-situ excitation in operating environment, was maintained as constant value with a fine tolerance during vibration testing. Range of input force was carefully selected to cover from the low magnitude excitation for linearly behaved tube motion to high magnitude of force for nonlinearly-behaved tube motion. Estimated critical damping ratio shows scatters in data and tends to increase as the magnitude of rising force and decrease with upward frequency variation. Larger size of support gap increases multi-span tube damping for high magnitude of excitation.

• Journal of the Korean Society of Clothing and Textiles
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• v.35 no.7
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• pp.713-720
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• 2011

This study investigated the effect of cold acclimatization training on body composition including weight, fat mass, and muscle mass with 10 subjects (5 males and 5 females). During the 3-week acclimatization training program, they visited an artificial climate chamber ($15^{\circ}C$) 15 times and were exposed to cold environment with light clothing for 2 hours. Body composition was measured before and after cold training using bioelectric impedance analysis that was later compared by a paired t-test. In the process of thermoregulation, muscle contraction was accompanied by increased substrate metabolism for rising heat production. After cold training, the muscle mass increased and fat mass decreased significantly (p<.1, p<.05), subsequently the body composition changed. It was found that cold acclimatization training could be used as a treatment for obesity. It was suggested that further investigation on the long term effects of mild cold exposure using clothing and its potential applicability as an obesity treatment.

• Child Health Nursing Research
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• v.14 no.3
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• pp.243-251
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• 2008

Objective: School nurses should be knowledgeable about attention-deficit hyperactivity disorder (ADHD) and have tolerant attitudes to children with ADHD. This study was done to identify school nurses' knowledge about, and attitudes to, ADHD. Methods: A cross-sectional descriptive correlational study was conducted. The participants were the 245 members of a school nurse association in C province in southern part of Korea. Data were collected using a self-report questionnaire. Descriptive statistics, t-test, ANOVA, and Pearson correlation coefficients were used to analyze the data. Results: Of the 245 packets mailed to members, 126 (51.4%) were returned, and of these, 122 packets (49.8%) were suitable for data analysis. School nurses in this study lack knowledge about ADHD. Moreover, school nurses reported low tolerance in their attitudes toward children with ADHD. There was no significant correlation between knowledge and attitudes in the management of ADHD among school nurses. Conclusion: Findings from this study show that school nurses have limited knowledge about ADHD and its treatment with stimulation medication. Moreover, their attitudes toward children with ADHD were in the low tolerant range. An educational program on ADHD for school nurses need to be developed and provided to facilitate the school nurses' role in assessing and caring for children with ADHD.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.2
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• pp.153-160
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• 2002

As a way to assess the reliability of programs for building energy analysis, verification experiment and calculation of heating load are simultaneously conducted for a well-defined test space. Experimental conditions are carefully set to minimize uncertainties associated with radiation heating, air change, infiltration, and room-to-room interaction. Dyna- mic load calculations using TRNSYS, which are performed for two different computation domains, rely on the energy rate control that represents inherent load characteristics of a space. The predicted instantaneous heating load favorably simulates the overall behavior the measured one, though the latter fluctuates much more rapidly than the former Comparison of the accumulative load between the experiment and calculations shows a close agreement within an engineering tolerance, regardless of the computation model. It is deduced from such findings that the present experimental results along with weather information can serve as a set of reference data for validating load calculation softwares from the users'standpoint. In order to enhance the completeness of this work, a complementary study on the cooling load for the same test space is highly recommended.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.163-166
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• 2002

OFDM should be used for the fourth generation communication for high speed communication. Because of high spectral efficiency and high tolerance to fading channel, OFDM is applied to many high speed wire and wirless communication such as DAB(Digital Audio Broudcast), DVB(Digital Video Broadcast), IMT 2000 etc. Inter-modulation, however, is derived from PAR(Peak to Average Power Ratio) of OFDM signals. The paper describes PTS(Partial Transmit Sequence) and SLM(Select Mapping) of an existing methods which can reduce PAR. And then the document introduces the new method that is called "Combine PAR method". The method proposed in this paper is to combine PTS and SLM. As a result of the simulation, Combine PAR method is better than the existing methods.g methods.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.6
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• pp.1051-1057
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• 2010

Database for the damage reference by armor piercing bullet test was established for both tube and plate specimens having a range of thickness. As the inclined angles of hit are increasing, it has been found that penetration damage diameter tends to increases accordingly in both specimen of the tube and plate, and such penetration damage diameter on the rear side becomes bigger than those on the front side. The tube specimen showed that the damage becomes bigger when central areas rather than the peripheral were hit. Through the plate test, it also has been found that the penetration ballistic limit for Al alloy is about 25.4mm and that of stainless steel about 12.7mm. From the fatigue analysis results using the database for damage reference, it has been identified whether the safety requirements of military aircraft could be met.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.1
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• pp.74-81
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• 2001

The sensorless scheme for Switched Reluctance Motor(SRM) drives must have the robustness and reliability because the noise and error are sensitive. These elements make electrically noisy environments due to the proximity of high current power circuits with small signal electronic circuits when SRM drives. Also, due to the leakage inductances and finite coupling capacitances, these can cause the noise on any low voltage current and voltage measurement circuit. The position estimate error occurs because the current and voltage including the noise are sued as the inputs of sensorless algorithm. In this paper the high robustness and resistance of input noise re described. The fuzzy logic based rotor estimation algorithm and the observer model are used to reduce the tolerance of input data.

• Current Optics and Photonics
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• v.2 no.3
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• pp.280-285
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• 2018

A new method to design a see-through off-axis head-mounted-display (OA-HMD) optical system with an ellipsoidal surface is proposed, in which a tilted ellipsoidal surface is used as the combiner, which yields the benefits of easier fabrication and testing compared to a freeform surface. Moreover, we realize a coaxial structure in the relay lens group, which is simple and has looser tolerance requirements, thus making assembly easier. The OA-HMD optical system we realize has a simple structure and consists of a combiner and 7 pieces of coaxial relay lenses. It has a $48^{\circ}{\times}36^{\circ}$ field of view (FOV) and 12-mm exit pupil diameter.