• Journal of Information Processing Systems
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• v.2 no.1
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• pp.39-43
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• 2006

In this paper, we proposed TASL-MAC, a medium-access control (MAC) protocol for wireless sensor networks. In wireless sensor networks, sensor nodes are usually deployed in a special environment, are assigned with long-term work, and are supported by a limited battery. As such, reducing the energy consumption becomes the primary concern with regard to wireless sensor networks. At the same time, reducing the latency in multi-hop data transmission is also very important. In the existing research, sensor nodes are expected to be switched to the sleep mode in order to reduce energy consumption. However, the existing proposals tended to assign the sensors with a fixed Sleep/Listening schedule, which causes unnecessary idle listening problems and conspicuous transmission latency due to the diversity of the traffic-load in the network. TASL-MAC is designed to dynamically adjust the duty listening time based on traffic load. This protocol enables the node with a proper data transfer rate to satisfy the application's requirements. Meanwhile, it can lead to much greater power efficiency by prolonging the nodes' sleeping time when the traffic. We evaluate our implementation of TASL-MAC in NS-2. The evaluation result indicates that our proposal could explicitly reduce packet delivery latency, and that it could also significantly prolong the lifetime of the entire network when traffic is low.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12C
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• pp.1035-1043
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• 2010

This paper presents a listening angle estimation scheme based on received signal power difference (RSPD) using acoustic signals, and analyzes the performance of the proposed scheme. The RSPD as the measurement to estimate the listening angle is considered for the first time in this paper. We mathematically analyze the error characteristics of the proposed scheme and present the characteristics of the proposed scheme through the Monte-Carlo simulation. We also conduct actual experiments in an anechoic room to evaluate the performance of the proposed scheme to compare with the conventional scheme.

• English Language & Literature Teaching
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• v.9 no.2
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• pp.263-291
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• 2003

This paper is to help the students in elementary schools develop and improve their English listening and speaking skills by presenting effective teaching and learning techniques using puppetry. It is absolutely obvious that listening and speaking are very important skills for most EFL students. Using puppets in the classroom is a creative English teaching technique which can involve authentic, communicative language situations. Moreover, puppets appeal to children and can aid in lowering affective filters thereby creating a more comfortable learning environment. The study clearly showed that using puppets is feasible and enjoyable in elementary English classes. However, caution must be exercised in drawing and generalizing conclusions from this experience. The results of the experiment are as follows: First, using puppetry in the English class was found to have positive influence on students' affective domains (interst, attitude). Second, using puppets in the English classes was found to be efficient for improving students' English listening and speaking skills. Third, appropriate materials should be selected and well thought-out plans should be made to be successful English class using puppetry. Perhaps the most interesting line of future research is to use qualitative research to examine the effect of this technique on the teacher variable. Further research is recommended, especially on using puppetry for speaking proficiency and creating affectively comfortable learning atmospheres.

• Journal of Fashion Business
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• v.21 no.6
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• pp.106-121
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• 2017

This study was to identify underlying dimensions of service encounter quality, to test difference in service encounter quality between interpersonal service(IPS) and self-service technology(SST) and to predict service effectiveness and behavioral intentions in the fashion retail context. A field experimental study was designed for collecting data. Repeat sampling frames were involved in two types of service encounters: interpersonal service and self-service technology within the store environment. Thirty participants served as subjects. Sample represents more females than males, and age was ranged from 20 to 33 years old (Mean=24.2). The result suggested that service encounter quality consisted of competence, dedication, and listening. There was a significant mean difference on listening factor of service encounter quality between IPS and SST. For the interpersonal service, dedication and listening had significant effects on service effectiveness. For the self-service technology, competence and listening had significant effects on service effectiveness. In the IPS condition, the service effectiveness significantly affected the revisit intention, whereas it was not significantly related to the revisit intention in the SST condition. This study discussed managerial implications for fashion retailers seeking to effectively manage service quality by specifying interpersonal service versus self-service technology in the retail environments.

• Phonetics and Speech Sciences
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• v.13 no.1
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• pp.17-24
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• 2021

In this study, listening errors by Korean EFL learners are comprehensively analyzed from self-paced passage dictation tasks. Fifty-five Korean EFL learners participated in the study. Listeners were asked to write down dictation passages as accurately as possible, while listening to the audio as much as they needed. The results show that (i) low-proficiency learners tend to misperceive longer phrases than high-proficiency learners, (ii) function words are more often omitted or misheard than content words, and (iii) low-proficiency learners have more difficulties with content words than high-proficiency learners do. Most frequent suffix errors were omissions of past or plural suffixes. Among the function words, the most frequent errors were found with auxiliary contractions, infinitive marker to, and articles, mostly in the environment of linking and elision. It is also shown that C-V linking, C-C linking, and elision are the primary sources for the most frequent errors. C-V linking led to errors in correctly locating the word boundary, while C-C linking and elision resulted in omission. These errors show that Korean EFL listeners have difficulties in detecting fine-grained phonetic details to the extent that native speakers can do.

• Journal of Environmental Science International
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• v.15 no.3
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• pp.287-292
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• 2006

The purpose of this paper is to evaluate the noise level and source, reduce the subway line II noise. As a result of measurement of subway line II in Busan the highest value section of uproad line was from Jigegol to Motgol by 89 dB(A). The sections of conversation and listening interference(over 80 dB(A)) were 21 sections(55%) of 38 sections. Among these sections, 15 sections(71%) were produced rolling noise, 3 sections(14%) squeal noise, 2 sections(10%) braking noise and 1 section(5%) fan noise, and then a main noise source was the rolling noise. In case of downroad line, the highest value section was from Busan Metro Art Museum to Centum city, Motgol to Jigegol by 88 dB(A). The sections of conversation and listening interference(over 80 dB(A)) were 18 sections(47%) of 38 sections. Among these sections, 15 sections(83%) produced rolling noise, 2 sections(11%) squeal noise and 1 section(6%) braking noise were investigated in this study. and then a main noise source was the rolling noise.

• The Journal of the Acoustical Society of Korea
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• v.40 no.1
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• pp.18-30
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• 2021

The ultimate goal of the present study is to establish the acoustical performance standards of classroom for the elderly who are incomplete hearing people. As a pilot survey, the present study was conducted to investigate the listening environment and the actual condition of speech perception performance of education facilities for elderly, Acoustic performances of two education facilities for elderly in Cheongju were measured and questionnaire survey was done to elderly people. Also, speech intelligibility tests were undertaken by Consonant Vowel Consonant (CVC) and Phonetically Balanced Words (PBW) methods. The questionnaire survey showed that the elderly were satisfied with the listening environment of the educational facilities in general. Also, it was found that acoustical performances satisfy with the acoustic criteria of general classrooms in Korea. However, the results of the speech intelligibility test showed that the scores of elderly were significantly lower than twenties with normal hearing. It was also revealed that the scores are reduced as the age increases. Thus, it was concluded that the acoustical performance standards of educational facilities for the normal hearing were not suitable for educational facilities for the elderly.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.5
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• pp.1-8
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• 2010

In this paper, a sound externalization method is proposed for out-of-the-head localization in a headphone listening environment. In order to reduce timbre distortion by the conventional methods using a measured a head-related transfer function (HRTF) or early reflections, the proposed method integrates a model-based HRTF with reverberation. In addition, for improving frontal externalization performance, techniques such as decorrelation and spectral notch filtering are included. To evaluate the performance of the proposed externalization method, subjective listening tests are conducted by using different types of sound sources such as white noise, sound effects, speech, and music. It is shown from the test results that the proposed externalization method can localize sound sources farther away from out of the head than the conventional method.

• Hwankyungkyoyuk
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• v.12 no.1
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• pp.40-63
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• 1999

As the environmental problems are recognized as daily problems in our lives, not as issues of those who are engaged in specific professional fields, the interest in environmental education is increasing gradually. The environmental education is the one that studies the environment and its problems and seeks the solutions for them. This paper deals with how the Korean subject will include environmental education. The environmental problems are already dealt with in the Korean textbooks according to the 6th curriculum for the Korean subject. A noticeable fact is that those textbooks connect the skills for language skills with environmental education. That is, the textbooks try to improve 4 language skills (speaking, listening, reading, and writing) with the Korean data related to environment, which can be the most practical means. This tendency will be also reflected in the 7th curriculum for the Korean subject, and the means will be taken by which environmental education will be able to be implemented more effectively through a variety of learning activities. In case of speaking and listening, learning activities such as speaking of, listening to, or discussing the contents concerning environmental problems can be recommended. In case of reading and literature, learning activities such as reading articles or works concerning environmental problems. Through these learning activities the Korean education will be able to achieve the goal in the fields of knowledge, information, and autonomy or attitudes which are the goals of environmental education. If the contents of the Korean curriculum are described in detail, it can be known that the Korean subject have someting to do with knowledge, skills, and recognition more deeply. In the methods In obtain information and knowledge, it will be desirable to recognize knowledge and information indirectly through various reading data rather than to recognize knowledge and information directly. Or it will be desirable to increase the sensitivity about environmental problems through literary works. For this environmental education in the above, we need to utilize discussion or presentation-oriented leaching and learning in the Korean education. Also we need to approach environmental problems by using various teaching media. We need to emphasize the education in the affective domain, especially through expression of emotions. guidance of reactions, internalization, personification, and so on.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.283-286
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• 2004

Due to advances in electronics very high quality audio reproduction is today possible. But the listening environment causes deviation of the audio system from the expected behavior. Firstly the listening Room significantly changes the audio signal frequencies and their phase. Secondly the position of the user in the room affects the perceived sound. With existing DSP technology it is possible to adequately correct these effects. In our work we developed a room correction system, correcting up to 7.1 channels using dual Motorola 56367 fixed point DSP's, implementing position dependent room effects measurement, real time compensation filter design and equalization filtering procedures.