• The Korean Journal of Food And Nutrition
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• v.24 no.3
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• pp.376-385
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• 2011

The purpose of this study was to estimate beverage consumption frequency and determine related problems of elementary school students in Chungnam. The survey was conducted with 488 students(boys=230, girls=258) using a questionnaire. The average age of the students was 10.1 years old, thir average height and weight were 145.1 cm and 39.5 kg, respectively and the obesity index was -1.3%. The frequencies for breakfast, lunch and dinner were 5.8 times/week, 6.7 times/week and 6.4 times/week, respectively. Regarding the frequency of snacks, high response rates for 'once/day'(38.3%) and 'none' (30.5%) were observed. Nutrition label on beverages were identified rarely(39.1%), nearly never(19.7%), and never(12.9%). The choice factors in selecting beverage were taste, nutrition, and price. For the type of snack most often consumed, fruit or juice was 25.8%, snack items were 25.2%, bread was 24.8%, dairy products were 7.6%, beverages were 7.0%, noddles were 6.2%, and rice cakes were 3.5%. The kinds of favorite beverages were carbonated drinks(30.3%), functional drinks (24.4%) and milk and yoghurt(23.8%), and main reason for the choice of beverage was "it tastes good". For the point of time that students wanted to drink a beverage, "when I feel thirsty" appeared most often for dairy products and beverages and the next most frequent answer was "after exercise". Therefore it may be necessary to administer systematic nutritional education on perception on nutrition fact label of beverage. And it is thought that plan for proper beverage consumption in elementary school students may be established.

• Smart Structures and Systems
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• v.22 no.2
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• pp.133-137
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• 2018

Increasing interest in prognostics and health management has heightened the need for wireless sensor networks (WSN) with efficient power sources. Piezoelectric energy harvesters using Pb(Zr,Ti)O3 (PZT) are one of the candidate power sources for WSNs as they efficiently convert mechanical vibration energy into electrical energy. These types of devices are resonated at a specific frequency, which has a significant impact on the amount of energy harvested, by external vibration. Hence, precise prediction of mechanical deformation including modal analysis of piezoelectric devices is crucial for estimating the energy generated under specific conditions. In this study, an experimental vibrational system capable of controlling a wide range of frequencies and accelerations was designed to generate mechanical vibration for piezoelectric energy harvesters. In conjunction with MATLAB, the system automatically finds the resonance frequency of harvesters. A small accelerometer and non-contact laser displacement sensor are employed to investigate the mechanical deformation of harvesters. Mechanical deformation under various frequencies and accelerations were investigated and analyzed based on data from two types of sensors. The results verify that the proposed system can be employed to carry out vibration experiments for piezoelectric harvesters and measurement of their mechanical deformation.

• Steel and Composite Structures
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• v.35 no.1
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• pp.111-127
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• 2020

The goal of this study is to fill this apparent gap in the area about investigating the effect of porosity distributions on vibrational behavior of FG sectorial plates resting on a two-parameter elastic foundation. The response of the elastic medium is formulated by the Winkler/Pasternak model. The internal pores and graphene platelets (GPLs) are distributed in the matrix either uniformly or non-uniformly according to three different patterns. The model is proposed with material parameters varying in the thickness of plate to achieve graded distributions in both porosity and nanofillers. The elastic modulus of the nanocomposite is obtained by using Halpin-Tsai micromechanics model. The annular sector plate is assumed to be simply supported in the radial edges while any arbitrary boundary conditions are applied to the other two circular edges including simply supported, clamped and free. The 2-D differential quadrature method as an efficient and accurate numerical approach is used to discretize the governing equations and to implement the boundary conditions. The convergence of the method is demonstrated and to validate the results, comparisons are made between the present results and those reported by well-known references for special cases treated before, have confirmed accuracy and efficiency of the present approach. It is observed that the maximum vibration frequency obtained in the case of symmetric porosity and GPL distribution, while the minimum vibration frequency is obtained using uniform porosity distribution. Results show that for better understanding of mechanical behavior of nanocomposite plates, it is crucial to consider porosities inside the material structure.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.3 s.345
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• pp.10-17
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• 2006

For orthogonal frequency division multiplexing (OFDM), cyclic prefix (CP) should be longer than the length of channel impulse response, resulting in a loss of bandwidth efficiency. In this letter, the CP reconstruction (CPR) technique is first applied to a multi-input multi-output (MIMO)-OFDM system with insufficient CP. The intercarrier interference (ICI) from multiple transmit antennas is so large for MIMO system that it can not be sufficiently suppressed with the conventional CPR procedure used in single-input single-output (SISO) system. A new minimum mean-square error (MMSE) equalization and ordering process is proposed for MIMO system to suppress the ICI during the CPR procedure. By applying the proposed CPR algerian to MIMO-OFDM system, we can obtain both the benefits of multiplexing gai and spectral efficiency gain.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.4 s.316
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• pp.70-77
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• 2007

Two kinds of QMF(Quadrature Mirror Filter) pairs are used in JPEG2000 standard, which don't have QMF distortions. However, the QMF pairs have the main disadvantages such that there are gentle roll-off rate, ripples in the passband and unequal band decomposition. In this paper, Maxflat(maximally flat) QMF pairs with a half-band gain are proposed for overcoming these problems. Maxflat QMF pairs are realized due to generalized closed-form formulas, and the filters have maximally flat response in the passband/stopband as well as sharp roll-off rate in the transition band. Comparing proposed filters and JPEG2000's filters in frequency domain, it is found that proposed filters have better performance JPEG2000's filters. Moreover, Maxflat QMF pairs show stopband-attenuation exceeding 200 dB almost everywhere.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.6 no.1
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• pp.75-81
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• 2012

This study in the treatment of autistic horse therapy of children with disabilities that affect the perception of parents is to some extent how well treatment for a sense of purpose and a horse therapy was to evaluate the expectations. As parents of autistic children with disabilities a questionnaire study of 100 people was used as a research tool. Analysis of the frequency analysis method, Chi-square Analysis were analyzed by taking advantage of each. Parents interested in horse therapy and children who do not have the experience of riding. In addition, Parents who have children age 10-20 riding in the response was that there would be effects Understanding mainly ride horses in the horse therapy is physical exercise. And therapy and exercise that combines specific area of expertise, as is the way to help. In addition, behavior modification, and it is used as a way to improve. Expectations in the therapeutic horse therapy should be major(occupational therapy, physical therapy, speech therapy). Horse therapy is suitable for individual therapy at least for 2-3 weeks and the Confederacy.

• International Journal of Knowledge Content Development & Technology
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• v.9 no.4
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• pp.7-29
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• 2019

The study was carried out to investigate the influence of demographics and social media use on perceived academic stress of secondary school students in St. Thomas Aquinas College, Akure, Nigeria. This was achieved using five research questions and four null hypotheses. The population of the study consisted of 1,107 students at ISCED level 3, out of which 286 were selected based on the Israel (2003) model for determining sample size. The Ex-Post Facto (EPT) research design of the correlational type was employed to investigate the study while questionnaire was used for data elicitation. Out of the 286 copies distributed, 192 (67% response rate) were retrieved and analyzed using descriptive statistics (frequency, percentage, mean and standard deviation) and inferential statistics (correlation and multiple regression). The findings revealed that there is high frequency of social media use among secondary school students, majorly for meeting new friends and chatting. The perceived academic stress (PAS) of the students was found to be moderate. Of the three demographics considered, only class had significant influence on PAS. Use of social media did not have significantly influence on PAS of the students. When combined, demographics and social media use predicted PAS; and when considered relatively, of the independent variables, only class as an aspect of demographics predicted PAS. Therefore, the authors concluded that PAS of secondary school students is not directly influenced by demographics (except for class) and social media use. Based on the study's conclusion, recommendations were made.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.7
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• pp.725-731
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• 2008

This paper focused on the application of finite element model updating technique to evaluate the structural properties of the reinforced concrete specimen using the data collected from shaking table tests. The specimen was subjected to six El Centre (NS, 1942) ground motion histories with different peak ground acceleration (PGA) ranging from 0.06 g to 0.50 g. For model updating, flexural stiffness values of structural members (walls and slabs) were chosen as the updating parameters so that the converged results have direct physical interpretations. Initial values for finite element model were determined from the member dimensions and material properties. Frequency response functions (i.e. transfer functions), natural frequencies and mode shapes were obtained using the acceleration measurement at each floor and given ground acceleration history. The weighting factors were used to account for the relative confidence in different types of Inputs for updating (j.e. transfer function and natural frequencies) The constraints based on upper/lower bound of parameters and sensitivity-based constraints were implemented to the updating procedure in this study using standard bounded variable least-squares(BVLS) method. The veracity of the updated finite element model was investigated by comparing the predicted and measured responses. The results indicated that the updated model replicates the dynamic behavior of the specimens reasonably well. At each stage of shaking, severity of damage that results from cracking of the reinforced concrete member was quantified from the updated parameters (i.e. flexural stiffness values).

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.65-65
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• 2000

Microwave response of intrinsic Josephson junctions in mesa structure formed on HgI2-intercalated Bi2Sr2CaCu2O8+x single crystals was studied in a wide range of microwave frequency. With irradiation of 73${\sim}$76 GHz microwave, the supercurrent branch becomes resistive above a certain onset microwave power. At low current bias, the current-voltage characteristics show linear behavior, while at high current bias, the resistive branch splits into multiple sub-branches. The voltage spacing between neighboring sub-branches increase with the microwave power and the total number of sub-branches is almost identical to the number of intrinsic Josephson junctions in the mesa. All the experimental results suggest that each sub-branch represents a specific mode of collective motion of Josephson vortices generated by the microwave irradiation. With irradiation of microwave of microwave of frequency lower than 20 GHz, on the other hand, no branch splitting was observed and the current-voltage characteristics exhibited complex behavior at hlgh blas currents. This result can be explained in terms of incoherent motion of Josephson vortices generated by non-uniform microwave irradiation.

• Korean Journal of Clinical Pharmacy
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• v.24 no.3
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• pp.206-212
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• 2014

Objectives: This was to evaluate the current usage of three erythropoietin stimulating agents (ESA) and their efficacy for management of anemia in peritoneal dialysis (PD) patients with chronic kidney disease. Methods: It was a retrospective comparative study through review of electronic medical records of chronic kidney disease patients undergoing PD at a tertiary teaching hospital from January 1998 to June 2013. Results: Average administration frequency was 1.66 times/week in EPO group, 0.75 times/week in DA group, and 0.19 times/week in MPG-EPO group. At the first 4 weeks, there were significant differences in mean hemoglobin levels between EPO and DA groups ($9.25{\pm}1.28g/dL$, $10.02{\pm}0.95g/dL$ each, p = 0.018) and also in hemoglobin response rates (10.0%, 45.2% each, p = 0.008), but since after 4 week, there had been no significant differences. There also showed no significant differences in achievement of hemoglobin target between the two groups. When converted to MPG-EPO in EPO/DA groups, there showed a slight increase in hemoglobin levels of both groups. MPG-EPO was the highest compared with two other drugs by the average cost based on the average weekly dose. Conclusion: EPO, DA, and MPG-EPO showed similar effects in treatment of anemia of PD patients based on hemoglobin target range (11.0~12.0 g/dL) which NFK-K/DOQI guidelines suggest. Though the average cost of MPG-EPO was higher than the other two drugs, the number of PD patients using MPG-EPO has increased and it is thought that long half-life and low administration frequency of MPG-EPO have improved the compliance of PD patients who have to self-administrate.