• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2013년도 추계학술대회 논문집
• /
• pp.854-855
• /
• 2013

As an unique acoustic characteristic of a Korean bell. beat phenomenon is a periodic repetition of strong and weak sounds. Beat sounds good when it is clear and it has a proper period, however, it is not easy to satisfy these two conditions simultaneously. In this study, we propose a beat tuning method to satisfy these two conditions, by using an equivalent bell model. First, we construct an equivalent bell which has the same beat property with the 1st beat of a real bell and we investigate the change of mode pair by finite element analysis, when thickness of the bell is locally decreased at $22.5^{\circ}$ from the striking point. From the analysis result, minimum thickness reduction amount is determined to make a clear and strong beat.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2013년도 추계학술대회 논문집
• /
• pp.708-712
• /
• 2013

The appearance of the Korean bell is exceptional comparing to that of other bells. The sound of the Korean bell is also distinguishable because of its remarkable appearance. The sound of the Korean bell is composed of striking sound and residue sound. This study focuses mainly on the striking sound of the Korean bell. The primary purpose of this study is to suggest a proper sound quality evaluation method for Korean bell. To implement this study, examine the formerly established methods which are method using rating method and method using generally used Psychoacoustics metrics. Also, subjective Sound Quality evaluation was conducted to compare the results of method using rating method and the method using psychoacoustics metrics.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2012년도 제38회 춘계학술대회논문집
• /
• pp.324-330
• /
• 2012

Dual bell nozzle is one of the most promising choices among the altitude adaptation nozzles. This facilitates having a forced, steady and symmetrical separation at lower altitudes and a controlled flow separation at the wall inflection point which prevents the generation of dangerous side loads. In order to ensure the attached flow in the second bell, a clear understanding of the flow transition is required. Hence the motivation of our study is to arrive at an optimum profile for the second bell, which allows a sudden and controlled transition. In this work, we designed the first bell using the conventional MoC and the second bell using an inverse MoC, imposing a pressure gradient constraint. A CFD analysis is also carried out. It is found that the separation point is near the inflection point within one fourth of the extension length or it is near the exit.

• Nonlinear Functional Analysis and Applications
• /
• 제26권4호
• /
• pp.733-747
• /
• 2021

Recently, Kim-Kim introduced Lah-Bell polynomials and numbers, and investigated some properties and identities of these polynomials and numbers. Kim studied Lah-Bell polynomials and numbers of degenerate version. In this paper, we study degenerate Lah-Bell polynomials arising from differential equations. Moreover, we investigate the phenomenon of scattering of the zeros of these polynomials.

• 한국멀티미디어학회논문지
• /
• 제18권8호
• /
• pp.968-979
• /
• 2015

In this paper, we study a vibration bell App which shows waiting sequence numbers by utilizing smartphones to solve an inconveniently long waiting time from ordering to getting foods in restaurants and coffee shops. Unlike existing independently developed hardware and software, the vibration bell App is developed to manage and integrate customer management service, POS service in shops, and group shop management services. The functions of the vibration bell App include two-way communications based on NFC- issuing waiting sequence numbers and electronic coupon, showing event information, and transferring user information. Furthermore, the user's personal information is minimized by recognizing the pre-existing information of the user's smartphone. Replacing the shop's vibration bell system with the vibration bell APP, the shops can reduce the cost of construction and maintenance by up to 1/10, compared to the cost of for existing vibration bell systems. Moreover, the customer's preference and current sales trend can be easily figured out. Thus, it will have a great effect on the future marketing strategies.

• 한국소음진동공학회논문집
• /
• 제13권8호
• /
• pp.626-636
• /
• 2003

The beat distribution property of the King Seong-deok Divine Bell is investigated by experiment and analysis. The beat map method is proposed to explain the beat distribution property on the circumference of the bell. For the analytical investigation, an analytical model of the vibration beat is derived on a slightly asymmetric shell of revolution by using the modal expansion method. In the analytical method, the beat map can be drawn only if the modal parameters of the bell are obtained. The analytical beat model is applied to draw the beat map of the King Seong-deok Divine Bell. The validity of the analytical method is verified by comparing the analytical beat maps with the experimental results. This paper proposes a visualization method of the beat and theoretically identifies the reason why the clear and unclear beats repeat periodically along the circumference of the bell and how the striking position influences the beat distribution property.

• 한국음향학회지
• /
• 제2권1호
• /
• pp.1-10
• /
• 1983

The presence of the sound tube and resonance cavity is unique in Korea Brahman Bells which is no examples in other country bells in the world. The sound tube erected in the crown is effective to emit the fundamental tone of the bell when the condition of resonant transmissibility is satisfied. The results of our analysis shows that the optimum length of the sound tube in the Bell Emile is 96cm but is not the present length, 77cm. The resonance cavity erected underneath the lip of the Bell Emile is found to be for the resonance of standing waves in the space including both bell cavity and resonance cavity and resonance cavity to the fundamental tone of the bell itself, in order that the strongest vibration can last long by least energy and lengthen the reverberation of the bell. Some historical remarks are also made on the magic flute, MANPASIKJUK, which was in existence in Shilla that can lull all evil waves, such as plagues, storms, droughts, famines and even enemies. The sound tube erected in the crown of the bell was originated in this magic flute. Finally, a strong proposal is advanced on the new national symbol of Korean traditional cultural assets. Indeed, it should be highly recommended that the Great King's Bell Emile would be the only real symbol of our national cultural assets by its own right of excellency and richness in every aspect of arts and sciences.

• 한국의상디자인학회지
• /
• 제19권1호
• /
• pp.91-105
• /
• 2017

A literature review and survey were conducted regarding the silhouette changes in bell bottom pants and the overall visual evaluation in accordance with the changes. The survey was disseminated from December 2015 to January 2016 to 245 women in their 20s living in Busan. The variables used for the silhouette changes in bell bottom pants were the volume of flare and the flare's starting point, and 20 pairs of terms were selected for visual evaluation. The results of the study are as follows: 1. Visual evaluations according to the volume of flare in bell bottoms indicated that females in their 20s appraised pants with a flare volume of 54 cm close to a straight silhouette and flare volume of 62 cm (recognized clearly as characteristic of bell bottom pants) to be more attractive and sophisticated than pants with flare volumes of 70 cm and 78 cm. 2.Visual evaluations according to the starting point of the flare in bell bottom pants showed that women appraised their legs as looking thinner when the flare started near the thighs. In a vertical visual evaluation, women appraised that their legs looked longer when the flare started near the knees and pants fit tightly around them. 3.The analysis of silhouette factors affecting the visual evaluation of bell bottom pants indicated that the volume of flare has more effect visually than the starting point of the flare.

• 한국음향학회지
• /
• 제30권4호
• /
• pp.223-230
• /
• 2011

한국종은 지면으로부터 일정한 간극을 두고 매달리며, 종 아래에 명동이라고 불리는 독특한 음향학적 요소를 갖고 있다. 간극과 명동의 적절한 설계는 공명효과에 의하여 종소리를 극적으로 증폭시킨다. 종체의 내부공동과 간극, 그리고 명동으로 구성된 음향공동계는 공명주파수와 모드를 갖는데, 공명주파수가 종체의 고유진동수에 일치하게 되면, 그 주파수성분이 크게 증폭된다. 이 연구는 성덕대왕신종을 대상으로 간극효과를 고려한 명동의 공명조건을 처음으로 제시한다. 공명조건을 구하기 위하여 신종의 실제 치수를 사용하여 SYSNOISE를 이용한 경계요소해석을 수행하였다. 또한, 계절에 따른 기온의 차이가 공명조건에 어떠한 영향을 미치는가를 규명하고, 가변형 명동의 개념을 제시함으로써, 현장에서 온도차를 보정하여 정확한 공명조건을 구현시킬 수 있는 방안을 제공한다.

• 한국산학기술학회논문지
• /
• 제21권7호
• /
• pp.176-183
• /
• 2020

구조함은 수색 및 구조작업을 위하여 크게 세 가지 형태의 잠수체계(Diver Stage Diving, Wet Bell Diving 및 Scuba Diving)를 보유하고 있다. 어떠한 잠수체계를 활용하더라도 잠수요원이 잠수작업 완료 후 상승 시에는 잠수병 예방을 위하여 잠수작업수심 및 잠수 총 시간에 해당하는 감압표에 따라 감압절차를 준수하여야 한다. 감압절차는 크게 수중감압방법과 수중 및 함상감압을 병행하여 수행하는 방법으로 나뉘게 된다. 특히 수중 및 함상감압을 함께 수행하는 방법의 경우 U.S Navy Diving Manual에 따라 수중감압에서 함상감압으로 넘어가는 단계인 Surface Interval이 5분을 초과하지 않아야 한다. 하지만 실선 테스트결과 Wet Bell Diving에서 Surface Interval이 5분을 초과하는 문제점이 발생하였다. 이에 본 논문에서는 모든 가능한 원인을 식별하여 원인분석을 실시하고, 이를 바탕으로 개선된 Wet Bell Diving의 측정결과를 나타내었다. 그 결과 개선된 잠수체계의 실선 테스트에서 Surface Interval이 5분 이내 만족함을 확인하였다. 본 논문의 연구결과는 향후 잠수체계의 운용 및 개선에 유용한 자료로 활용될 것으로 판단된다.