• 한국해양공학회지
• /
• 제36권1호
• /
• pp.61-81
• /
• 2022

The available underwater acoustic spectrum is limited. Therefore, it is imperative to avoid frequency interference from overlapping frequencies of underwater acoustic equipment (UAE) for the co-existence of the UAE. Cognitive technology that senses idle spectrum and actively avoids frequency interference is an efficient method to facilitate the collision-free operation of multiple UAE with overlapping frequencies. Cognitive technology is adopted to identify the frequency usage of UAE to apply cognitive technology. To this end, we investigated two principle underwater acoustic sources: UAE and marine animals. The UAE is classified into five types: underwater acoustic modem, acoustic positioning system, multi-beam echo-sounder, side-scan sonar, and sub-bottom profiler. We analyzed the parameters of the frequency band, directivity, range, and depth, which play a critical role in the design of underwater acoustic cognitive technology. Moreover, the frequency band of several marine species was also examined. The mid-frequency band from 10 - 40 kHz was found to be the busiest. Lastly, this study provides useful insights into the design of underwater acoustic cognitive technologies, where it is essential to avoid interference among the UAE in this mid-frequency band.

• 한국지리정보학회지
• /
• 제11권3호
• /
• pp.118-126
• /
• 2008

본 연구에서는 부산광역시를 대상으로 한 도시계획분야에서의 GIS를 활용한 토지이용분석 방법을 제안했다. 본 연구에서 사용한 부산광역시의 도시계획정보시스템 데이터베이스는 2000년대 초반에 구축되어졌다. 건물데이터는 수치지도(1:1,000)를 이용하였으며, 건축물대장과 수치지적도로부터 건물용도 현황 및 용도지역 지정현황 등의 속성을 입력한 것을 사용했다. 그리고, 특화계수의 산출로 부산광역시의 토지이용특성을 명확히 했으며 용도지역별로 특화범위를 비교했다. 또한, 건물용도별 및 용도지역별 관찰도수와 기대도수를 오버레이분석으로 산출하여 비교 분석한 결과 용도지역에 의해 건축물의 용도가 유도되고 있음을 알았다.

• 이베로아메리카
• /
• 제23권1호
• /
• pp.1-31
• /
• 2021

본 연구의 주요 목적은 포르투갈어 a gente의 사용 현실에 대해 살펴보고, 교육적으로 고려할 부분에 대하여 논의해 보는 것이다. 우리는 언어적, 사회적 측면에서 a gente의 유래와 사용 환경, 문법화 단계, 개인화 등급, 사용의 변이에 대한 살펴보았고, a gente가 브라질에서 점점 높은 사용 빈도를 보여 주고 있음을 확인하였다. 그리고 교육적으로 고려할 부분을 찾기 위해, 외국인을 위한 포르투갈어 교재에 a gente가 어떻게 다루어지고 있는지 관찰해 보았고, 브라질에서 포르투갈어를 학습 중인 세 명의 한국인 학생과의 인터뷰 조사를 통해 얻은 자료를 분석해 보았다. 1인칭 복수 nós와 의미가 같지만 3인칭 단수 형태로 사용되는 a gente의 중요성과 사용 빈도를 감안해 보면, 문법이나 교재에서 다루어지는 a gente에 대한 부분은 매우 미흡해 보인다. 따라서 실제 언어 사용에 부합하지 않는 교재의 내용들은 언어 사용 현실의 변화에 따라 적극적으로 수정되어야 할 것이다. 그리고 교수자 역시 전통적인 부분에 얽매이지 말고 효율적인 교육을 위해 a gente를 교재의 인칭 대명사 편에 확실히 포함하여 좀 더 실용적인 부분을 적극 반영하여 교육하여야 할 것이다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제16권2호
• /
• pp.713-725
• /
• 2022

Mostly, artificial intelligence does not show any definite change in emotions. For this reason, it is hard to demonstrate empathy in communication with humans. If frequency modification is applied to neutral emotions, or if a different emotional frequency is added to them, it is possible to develop artificial intelligence with emotions. This study proposes the emotion conversion using the Generative Adversarial Network (GAN) based voice frequency synthesis. The proposed method extracts a frequency from speech data of twenty-four actors and actresses. In other words, it extracts voice features of their different emotions, preserves linguistic features, and converts emotions only. After that, it generates a frequency in variational auto-encoding Wasserstein generative adversarial network (VAW-GAN) in order to make prosody and preserve linguistic information. That makes it possible to learn speech features in parallel. Finally, it corrects a frequency by employing Amplitude Scaling. With the use of the spectral conversion of logarithmic scale, it is converted into a frequency in consideration of human hearing features. Accordingly, the proposed technique provides the emotion conversion of speeches in order to express emotions in line with artificially generated voices or speeches.

• 전기학회논문지
• /
• 제63권3호
• /
• pp.371-375
• /
• 2014

In this paper, we compared the performances of the Right Handed Transmission Line (RHTL) and the Left Handed Transmission Line (LHTL) phase shifters as a frequency translator. Unlike other phase shifters, both phase shifters show a $0^{\circ}-360^{\circ}$ phase variation for a broadband frequency and compact in size which are ideal to use as a frequency translator. For the performance comparison, we fabricated both a RHTL and a LHTL phase shifter to cover 1.5 GHz - 2.4 GHz range with the whole $360^{\circ}$ phase variation. For the frequency range, a LHTL based frequency translator showed a much better performance whose Spurious Free Dynamic Range (SFDR) is 4dB - 17dB higher than the RHTL based frequency translator when the sawtooth modulation freqncy is 11 kHz. This is due to the linear phase-voltage variation of LHTL phase shifter. Furthermore, the LHTL phase shifter shows a less insertion loss and a insertion loss variation than the RHTL phase shifter. Overall, the LHTL based frequency translator outperformed RHTL based freqency translator.

• 대한기계학회논문집
• /
• 제18권4호
• /
• pp.1050-1056
• /
• 1994

When a vibration data for a rotating machine such as a pump or a compressor is concerned, the frequency fluctuation of the energy contents at an instant time may provide useful information on understanding the vibration characteristics of the rotating machinery, rather than the averaged energy distribution along the frequency axis. Especially, when a periodic signal has different spectral contents, the approach to use the averaged frequency distribution, called the normal frequency analysis, may not be appropriate to extract vibration source characteristics of the structure. This paper introduces a way to analyze the signal based on an instant time. In order to evaluate the performance of the various approach, the investigatation compares three different algorithms which are frequently implemented in the instantaneous frequency analysis. Also for the noise effect embodied in the true signal, various cases for different SN ratio have been examined. The result shows that the noise level is crucial to evalute the instantaneous frequency analysis. In order to implement the instantaneous frequency analysis, the extraction of the relevant information from the measured signal should have the high S/N ratio, i, e., 40 dB or above.

• Nuclear Engineering and Technology
• /
• 제49권2호
• /
• pp.373-379
• /
• 2017

Seismic probabilistic safety assessments are used to help understand the impact potential seismic events can have on the operation of a nuclear power plant. An important component to seismic probabilistic safety assessment is the seismic hazard curve which shows the frequency of seismic events. However, these hazard curves are estimated assuming a normal distribution of the seismic events. This may not be a strong assumption given the number of recorded events at each source-to-site distance. The use of a normal distribution makes the calculations significantly easier but may underestimate or overestimate the more rare events, which is of concern to nuclear power plants. This paper shows a preliminary exploration into the effect of using a distribution that perhaps more represents the distribution of events, such as the t-distribution to describe data. The integration of a probability distribution with potentially larger tails basically pushes the hazard curves outward, suggesting a different range of frequencies for use in seismic probabilistic safety assessments. Therefore the use of a more realistic distribution results in an increase in the frequency calculations suggesting rare events are less rare than thought in terms of seismic probabilistic safety assessment. However, the opposite was observed with the ground motion prediction equation considered.

• 대한인간공학회지
• /
• 제24권4호
• /
• pp.73-78
• /
• 2005

As the number of functions in a menu increases, users have more difficulties in finding a desired function. Previous studies have shown that some functions are selected more frequently than others, and have suggested adaptive menus that support the selection of frequently used functions. Interestingly, studies on an adaptive toolbar are not easy to find as opposed to many studies on adaptive menus. This study suggested an adaptive toolbar (AT) that supported function selection, and conducted a usability test. Five or ten functions were presented in the AT according to the frequency of use or recency of use. A total of sixteen males in their twenties participated in the test. They freely selected functions from the menu or from the AT, and their pattern of selecting functions was analyzed. The results showed that the AT was more frequently used than the menu as time passed. The AT based on the recency of use showed more effective performance than that based on the frequency of use. In addition, keeping ten functions was better than five functions in terms of both performance and preference.

• 한국멀티미디어학회논문지
• /
• 제23권4호
• /
• pp.588-594
• /
• 2020

This study analyzes the current status of drone journalism in Korean broadcasting industry, with a case study of TV Chosun Company's drone use for news gathering. It analyzes TV Chosun's record of drone logs between 2014 and 2018. The log consists of date, time, news content, users, machine and on-air date. In 2014, the total of 31 cases of using drones for news gathering is identified, while in 2018, the frequency increases to 60, with a gradual, annual increase, making the total frequency of 160, during the period between 2014 and 2018. This means that the broadcasting company used the drone news gathering system every week. The analysis also reveals that the company used this drone news gathering system mostly in the metropolitan area in Korea, amounting to more than 76 per cent of its total use: 31.3 per cent in Seoul, 36.9 per cent in Kyunggi, and 8.1 percent in Incheon. The system was more frequently used in the summer and autumn than the winter and spring. Interestingly, it was first popularly used for disaster related news, but the use of drone for social and other issues is increasing every year, which may imply its diverse use in the future.

• 한국비블리아학회지
• /
• 제35권2호
• /
• pp.109-133
• /
• 2024

본 연구는 생성형 인공지능(Generative AI)의 기술적 특성과 도서관 사서의 개인적 특성이 생성형 AI 사용의도에 미치는 영향을 분석하였다. 이를 위해 본 연구는 생성형 AI 사용의도에 영향을 미치는 요인으로 개인화, 상호작용, 맥락 인지를 생성형 AI의 기술적 특성으로 투입하고, 혁신성과 사용빈도를 사서의 개인적 특성으로 투입하였다. 연구대상은 도서관에서 재직 중인 사서 187명이 대상이며, 이 중 165부의 설문지를 수집하여 분석에 사용하였다. 연구결과, 생성형 AI의 기술적 특성은 생성형 AI의 사용의도에 통계적으로 유의미한 영향을 미치는 것으로 나타났고, 사서의 개인적 특성인 혁신성과 생성형 AI 사용빈도 역시 모두 생성형 AI의 사용의도에 유의미한 영향을 미친 것으로 나타났다. 본 연구의 결과는 도서관 사서들이 생성형 AI 사용의도를 높여 도서관 서비스의 질과 만족도를 제고하는 중요한 기초자료로 활용될 것이다.