• Steel and Composite Structures
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• v.47 no.6
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• pp.743-757
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• 2023

In this paper, the dynamic response of a simply-supported composite sandwich plate with a viscoelastic core based on the Golla-Hughes-McTavish (GHM) viscoelastic model is investigated analytically. The formulation is developed using the three-layered sandwich panel theory. Hamilton's principle has been employed to derive the equations of motion. Since classical models, like kelvin-voigt and Maxwell models, cannot express a comprehensive description of the dynamic behavior of viscoelastic material, the GHM method is used to model the viscoelastic core of the plate in this research. The main advantage of the GHM model in comparison with classical models is the consideration of the frequency-dependent characteristic of viscoelastic material. Identification of the material parameters of GHM mini-oscillator terms is an essential procedure in applying the GHM model. In this study, the focus of viscoelastic modeling is on the development of GHM parameters identification. For this purpose, a new method is proposed to find these constants which express frequency-dependent behavior characterization of viscoelastic material. Natural frequencies and loss factors of the sandwich panel based on ESL and three-layered theories in different geometrics are described at 30℃ and 90℃; also, the comparisons show that obtained natural frequencies are grossly overestimated by ESL theory. The argumentations of differences in natural frequencies are also illustrated in detail. The obtained results show that the GHM model presents a more accurate description of the plate's dynamic response by considering the frequency dependency behavior of the viscoelastic core.

• Journal of Dairy Science and Biotechnology
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• v.29 no.2
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• pp.25-35
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• 2011

The objectives of this study were to evaluate the sensory characteristic quality of commercial milk brands selling in the market under the preservation at the temperature of $7^{\circ}C$ and $10^{\circ}C$ stored during the period of shelf-life. Quantitative descriptive analysis after developing of descriptive terms and cluster characterization by PCA analysis over a total of 128 LTLT, HTST, UHT and UHT-ESL milks, were conducted by 8 trained panelists. A total of fourteen attributes; three aroma attributes (grassy, milky, cultured milk aroma) and seven flavor/taste attributes (sweet, salty, sour, milk, cooked, cheesy, paper board) and one aftertaste attributes (rancid flavor) and one texture attributes (viscous), were developed as descriptive terms. Significant differences (P<0.01) in the sensory attributes; sweet, milky, cheesy etc. in UHT milk and sour, cheesy, paper board, rancid etc. in UHT-ESL milk were also found between the two different temperatures within the shelf life, but both type of pasteurized milk samples (LTLT and HTST) showed significant differences (P<0.01) in the attributes, such as cultured milk aroma, salty, sour, cheesy, rancid in LTLT milk and grassy, milky, salty in HTST milk and difference (P<0.05) in cultured milk aroma for HTST milk. Therefore, from the viewpoint of not only hygienic quality but also sensory characteristics, it is required for the better acceptance of milk consumers to amendment on the regulation in relation to the preservation standard of pasteurized milk as well as UHT milk to lower than $7^{\circ}C$.

• English Language & Literature Teaching
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• v.17 no.3
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• pp.309-326
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• 2011

This study examines the relationship between second language use outside of class and oral proficiency development. It first identifies out-of-class activities of international graduate students in the U.S. and the average time spent speaking English in those out-of-class activities. Interviews and student self-measurements of time spent speaking English each day were used to investigate the types and quantities of out-of-class activities. In addition, two sets of student oral proficiency test scores were collected. Correlation analysis is used to find out the relationship of the variables between the most salient out-of-class activities and oral proficiency gains. The findings indicate that second language use outside of class is important for international graduate students to improve their oral proficiency. This is especially true with regularized interaction such as talking at work and the average time spent speaking in English a day outside of class. This study suggests that learners of English in an ESL environment should be encouraged to take part in out-of-class activities in addition to English use in the classroom in order for them to improve their oral proficiency.

• English Language & Literature Teaching
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• v.12 no.1
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• pp.1-27
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• 2006

This study investigated how EFL readers critically read texts which are written in English. Although critical reading has been discussed in advanced EFL and ESL contexts there has not been much research on the critical reading of beginning EFL learners. Many educators are recommending that a critical perspective be adopted so that L2 learners can become empowered rather than indoctrinated. In this study, the researcher has examined the critical reading practices of five beginning level EFL readers in Korea and five first language readers of English in the United States as they read a news editorial article. The significant findings were discussed related to critical reading practice of L2 readers. The findings of the study can help the educators in English education in improving the curriculum, the teaching methodology and the learning theory for EFL reading for critical reading.

• Korean Journal of English Language and Linguistics
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• v.3 no.2
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• pp.233-254
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• 2003

This paper analyzed the effect of using a content-based English textbook in teaching English to Korean college students. The textbook reflected the recent trend in EFL/ESL development that subject matters should be taught as part of the language instruction. The analysis of the questionnaire survey conducted to college students at the end of the semester revealed an encouraging result that this new type of ELT college textbook is effective in helping Korean college students prepare for learning their subject areas through English. Based on this positive outcome, a suggestion is made that the current general purpose college English teaching curriculum be shifted toward a content-based specific purpose type to accommodate the increasing demand of learning subject areas through English in colleges in Korea.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.148-150
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• 2016

다국적 선원으로 구성된 선박환경에서 근무하는 선원들에게는 원활한 의사소통을 위한 영어구사능력뿐만 아니라 서로 다른 문화에 적절히 대응하고 융합하는 이문화 커뮤니케이션 능력함양이 절대적으로 요구된다 할 것이다. 특히 필리핀, 중국, 인도, 일본, 인도네시아, 한국, 미얀마를 비롯한 아시아 선원들이 전 세계 선원시장에서 차지하는 비중이 50%에 달하는 점과, 이들 국가들이 영어를 모국어로 사용하고 있지 않은 점을 고려할 때, 아시아 지역 선원들에 대한 해사영어 교육훈련의 중요성은 아무리 강조하여도 지나치지 않을 것이다. 따라서 이 연구에서는 아시아해사영어교육센터에 대한 구성과 역할 및 향후 추진방향 등을 제시하고자 한다.

• English Language & Literature Teaching
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• no.4
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• pp.207-228
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• 1998

This study investigated how Korean learners of English acquired the English reflexives. There is emphasis on the effects of the GCP and PAP(Wexler and Manzini, 1987). The purpose is to examine the major hypothesis that L2 learners are still constrained by Universal Grammar (UG), despite the influence of the parameter setting of their native language as well as the non-operation of the Subset Principle. The experimental group consisted of 30 middle school students (age 14-15), 30 high school students (age 16-17), and 30 university students (age 18-19) as well as 20 ESL students (age 16) studying English in the USA. Twenty native speakers of English served as a control group. The subjects responded to a test on reflexives that used a multiple-choice grammaticality judgement task. Findings show that L2 learners transfer their L1 parameter setting and, as a result, make errors in the choice of antecedents for reflexives. Therefore, I argue that the L2 learner is still constrained by UG.

• English Language & Literature Teaching
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• no.5
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• pp.1-25
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• 1999

The objective of the present study was to model the relationships between language learning strategy use and language proficiency among the Asian (Korean, Japanese, and Taiwanese) students studying English in the United States. The instruments were a language learning strategy Questionnaire and the Institutional Testing Program Test of English as a Foreign Language (ITP TOEFL). Structural equation modeling was utilized to model the relationships between language learning strategies and language proficiency. The present study found only weak relationships between language learning strategies and language proficiency. Only 13% and 15% of variance of the listening and grammar/reading factor were explained by the language learning strategies. The metacognitive strategies appeared not to have direct relationships to the language skill factors, as was found in other studies (Purpura, 1996, 1997). The effects of the social and affective strategies were very small. They in combination could account about 1% and 4% of the variance of the listening and grammar/reading factors.

• English Language & Literature Teaching
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• v.13 no.4
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• pp.109-126
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• 2007

English article has been considered as one of the most difficult areas to learn among ESL/EFL students. The current paper reviews English learners' article error patterns as well as pedagogy in order to teach English articles and to minimize learning difficulties on English articles. Different pedagogy for English articles on the basis of learners' proficiency levels are suggested as each proficiency level student shows a different error tendency; beginning level language learners used the zero article with the most facility while intermediate level language learners used the definite article the most accurately. However, studies about high advanced level learners' error patterns present that these high accuracy rates among beginning level students might be a result of students' plain guessing. Considering these error patterns, pedagogy for advanced level is also suggested.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.2
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• pp.75-80
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• 2014

Energy consumption of sensor nodes is minimized because it has limited energy generator in wireless sensor network. Electronic shelf label system is one of application fields using wireless sensor networks. Battery size of small apparatus for displaying price is restricted. Therefore its current consumption have to be minimized. Furthermore the method for minimization of peak current would be considered because life cycle of coin battery used to display or RF is vulnerable to intensity of drain current. In this paper, we analyze current consumption pattern of low-power electronic shelf label system. Then we propose the method for minimization of current consumption by modification of software and hardware. Current consumption of the system using proposed method are approximately 15 to 20 percent lower than existing system and the life cycle of the system is approximately 10 percent higher than existing system.