The ship security accidents that occur in ships, at sea, and in ports have become increasingly more serious in recent years, and in particular, maritime terrorism and the abduction by pirates are emerging as an international problem. Accordingly, the International Maritime Organization implemented a measures to enhance ship security by adopting SOLAS Chapter 11-2, ISPS-code in 2004. In this study, it was investigated whether JDS-S4, a directional sound receiver developed for responding to ship security accident, has durability and safety suitable for ships. For the purpose, the conducted emission test (CE102) of the US military standard test (MIL-STD-461F) was performed, and it was confirmed that JDS-S4 satisfies the test conditions sufficiently.

Speaker is the converting device which change electric energy to sound energy, and we can easily see the speaker. They are widely used to home and car audio unit, home and industrial alarm device. Sometimes, the alarm sounds cause the environmental noise. Therefore it is important to design the appropriate speaker according to the installed device and position. In order to study the vibration and sound characteristics, the curvature of the cone paper is changed. Finite element method is used to compute the vibration characteristics and mode. Indoor and Vehicle teats are carried out to investigate the non-linear characteristics and the sound characteristics for some car speakers.

Most of speakers, the con-paper (con shape) or vibration plate generate the sound by reciprocating motion which is received vibrating signal from voice coil. On the other hand, the vibration speaker that reproduces sound by attaching a vibration head to some materials such as wood, plastic, glass plate, etc. instead of cone paper or vibration plate generates different sound timbres depending on the attached materials with vibration head. so we can hear a variety of timbres than ordinary speakers. In this study, the characteristics of vibration and sound propagation according to various materials attached to the vibration head of the vibration speaker were experimentally investigated and this sound propagation characteristics were compare with woofer speaker and micro speaker. As a result of sound propagation characteristics of vibration speaker, the reproduction ability of low frequency band wes inferior to compared than woofer speaker and micro speaker. This is judged to be due to the material characteristics of glass and wood which are source of the sound propagation. As compare with 1kHz sine tone, the woofer speaker has not generated the high order harmonic component, but the glass plate and wood plate used with the vibration speaker head have generated the high order harmonic component at a level that can not be ignored. According to above results, the vibration speaker will be had a low articulation of sound because the higher volume to generate the high distortion.

The security accidents occurring in ships and at seas and ports became very serious, and in particular, the maritime terrorism and abduction by pirates have emerged at the international level as a problem. The international maritime organization (IMO), accordingly, entered into such forces as the SOLAS chapter and measures in order to reinforce the maritime security and the security for ships and port facilities in 2004. In this study, the JDS-S4 improved as an oriented speaker to reinforce the ship security by enabling the clear communication even at long distance was tested by using the conducted emission test(CE101) and a standard test of the US military standard (MIL-STD-461F). Also, the result of this study was shown to satisfy the standard.

In the car speaker, because the sound characteristics is changed by the space of car which mount the speaker, the speaker elements must be decide according to sound field. In this study, the nonlinear characteristics, the frequency response and the sound pressure for the same size speakers which is adapted to domestic car model are investigated. The car model is classified to semi-midsize, midsized, full size automobile in order to change the car space. As a results, we can investigate the differences of the force factor and the stiffness of suspension system for speaker. According to the change of the speaker characteristics, the sound pressure is changed, also. In the future, these data will be used to investigate the correlation between the sound quality and measurement data.

최근 홈로봇에 대한 관심이 인공지능의 발전과 함께 급증하고 있다. 단순히 대화가 가능한 로봇이 아니라 소니의 아이보와 같은 펫로봇 형태를 비롯해 교육, 엔터테인먼트, 안내, 청소와 같은 각기의 세부적인 기능에 특화되어 있는 로봇들이 속속들이 우리 앞에 나타나고 있다. 한편, 클라우드기반의 인공지능 알고리즘과 음성인식을 이용한 AI스피커가 단순히 소리를 전달하는 기능을 뛰어넘어 명령을 알아 듣고 이를 실행하거나 이에 대한 답을 제공하는 기기로 진화하고 있다. 이러한 기능의 변화는 텍스트에서 그래픽유저인터페이스로 진화된 MMI(Man-Machine Interface)의 새로운 세대를 예고하고 있다. 본 연구에서는 홈로봇의 현황과 홈로봇에 적용될 ABI(Audio Base Interface, 음성기반인터페이스)로서 AI스피커에 대해서 고찰하고 있다.

As emphasis has increased on English as an international language and on the globalized image of universities, the number of native English speaker teachers (NETs) has also increased in Korean universities. From the poststructuralist view, teacher identity is constructed through participation in valued activities of the community of practice, and it is not fixed but constantly negotiated through the interaction of the context (Wenger, 1998). While previous studies focused on nonnative English speaker teachers’ identity construction, little attention has been paid to NETs in the EFL context. Considering the need to explore teacher identity from recent theoretical perspectives, the present study investigates how NETs negotiate conflicting identities and construct their teacher identities in the Korean university context. The findings show the NETs constructed multiple identities of an English educator, a collaborative volunteer, a non-tenured instructor, and a cultural and linguistic outsider, and they legitimize their professor identity through their participation in the present and imagined community of competent teachers. The findings support the claim that teacher identity is embedded in the sociocultural context that interacts with the individual agency in making sense of who they are. Implications and suggestions of the study are addressed based on the findings.

The characteristic test define the thiele-small parameters and the speaker is modeled to linear or non-linear model by thiele-small parameters. The performance test is carried out the sound quality by feeling test(subjective test) and objective test. The feeling test has many problems in a viewpoint of reliability, repeatability and preference that are related to judge. The study on the correlation between feeling test and objective test are carried out in some researches and introduce the loudness, sharpness, roughness and fluctuation strength. In this study, the loudness characteristics, which is related to sound quality, of the woofer speaker that are fitted to the domestic vehicle is investigated by measurement

In the car speaker, because the sound characteristics is changed by the space of car which mount the speaker, the speaker elements must be decide according to sound field. In this study, the mass of cone paper and damper is changed and the characteristics of the sound pressure and loudness are investigated by the experimental approach. According to the change of the speaker characteristics, the sound pressure and loudness level are changed. The effect of the con paper is larger than that of the damper in the aspect of the loudness. In the future, these data will be used to investigate the correlation between the sound quality and measurement data.

The sound characteristics is changed by the cabin of the car which mount the speaker. Therefore the speaker must be design to consider the cabin of the car. In this study, the mechanical components of the nonlinear speaker model are investigated by measurement. The frequency characteristics of the sound and the sound pressure level for the same size speakers which are adapted to domestic car model(semi-mid size & mid size car) are investigated, too. From the measurement, we can investigate the differences of the sound characteristics and the thiele-small parameter such as force factor, mechanical mass of driver diaphragm, mechanical resistance of driver suspension losses and mechanical stiffness of driver suspension. This means that the speaker design parameters are changed by the car model

The automotive speaker is modeld to nonlinear speaker model using the large signal performance measurement. In order to study the characteristics for the mass of cone paper and damper, the mass of the cone paper and damper is changed and the nonlinear parameters of the speaker are studied using the experimental approach. From measurement data, the effect on force factor, compliance(stiffness), resonance frequency, Q-factor is investigated by changing the conpaper and damper.

The present study investigated native speaker teachers’ beliefs about learning and teaching English in the Korean university setting. Despite the great influx of native speaker teachers into the Korean English education system, relatively little research has been carried out on teachers’ perspectives on learning and teaching. Considering the significant impact of teachers’ beliefs in the classroom, this study investigated the sources of teachers’ beliefs, their beliefs about learning and teaching, and their beliefs about teacher roles in the second language classroom. Data were collected through semi-structured interviews with eight native English speakers who were teaching at the same university. The findings showed that the teachers believed students’ active participation was the key to successful second language learning. It was shown that the teachers’ beliefs were closely associated with their prior learning experiences and that differences in the learning experiences between the teacher and students may cause difficulty in the second language classroom. These findings suggest the importance of teachers’ awareness of students’ learning experiences and the need to negotiate within the given teaching context without completely giving up teachers’ own beliefs about learning and teaching a second language.

Information technology devices, such as cellular phones, MP3s and so on, due to restrictions of space, require thin and small micro-speakers to generate sound. The reduction of the size of micro-speakers has resulted in the decrease of sound quality, due to such factors as frequency range and sound pressure level. In this study, the acoustical properties of oval microspeakers has been studied as a function of pattern shape on the diaphragm. The other conditions of micro-speakers, except for the pattern, was not changed. When the pattern is present on the diaphragm and the shape of pattern was a whirlwind, the resonance frequency was reduced due to the decrease of tensile strength of diaphragm. The patterns presented in the semi-minor axis of diaphragm did not effect a change of resonance frequency. However, increasing the number of patterns in the semimajor axis of diaphragm became a reason for the decrease of resonance frequency on edge side. When the depth of pattern on edge side was increased, the resonance frequency was decreased due to reduction of geometrical stiffness. If the height of edge and dome were increased, the resonance frequency and geometrical stiffness rapidly increased. After reaching the maximum values, they began to decrease with the continuous increase of height.

This study is an attempt to make a detailed description of the pronunciation features of an African American speaker from Cleveland, Ohio in the U.S.A. Most of the description is devoted to the pronunciation features of the subject's speech even though some lexical and grammatical aspects will also be noted. The present study shows that despite some apparent pronunciation differences, the subject's speech and the Standard American English share essentially the same underlying phonemic inventories. Even though no systematic attempt to associate it with any given social or regional dialect is made, the subject's speech is assumed to belong to the Great Lakes Dialects. The subject's speech was observed to exhibit some influence of the Northern Cities Shift, a chain vowel shift observed in the Great Lakes Dialects, yet, the influence was sporadic lexically: the vowel shift was not complete enough to posit an altered phonemic system for his speech. Granting this, even the limited findings of the present study imply that the subject's speech does indeed exhibit influence of the on-going sound change in the region and makes an excellent material for further study of the gradual sociolinguistic sound change.