Transparent and flexible force sensor array based on optical waveguide.

Kim, Youngsung,Park, Suntak,Park, Seung Koo,Yun, Sungryul,Kyung, Ki-Uk,Sun, Kyung Optical Society of America 2012 Optics express Vol.20 No.13

<P>This paper suggests a force sensor array measuring contact force based on intensity change of light transmitted throughout optical waveguide. For transparency and flexibility of the sensor, two soft prepolymers with different refractive index have been developed. The optical waveguide consists of two cladding layers and a core layer. The top cladding layer is designed to allow light scattering at the specific area in response to finger contact. The force sensor shows a distinct tendency that output intensity decreases with input force and measurement range is from 0 to -13.2 dB.</P>

Design of transparent multilayer film antenna for wireless communication

Youngsung Kim,Changmin Lee,Seungman Hong,Chang Won Jung,Yongjin Kim IET 2015 Electronics letters Vol.51 No.1

<P>A multilayer thin film antenna for mobile devices is proposed. The proposed antenna consists of a (indium-zinc-tin oxide) IZTO/Ag/IZTO multilayer film, which is fabricated on a polyimide substrate (ε<SUB>r</SUB> = 3.5) and a copper layer. The centre frequency of the antenna is 1260 MHz. The geometry of the antenna is made up of a coupled loop and two branches. The proposed antenna was fabricated using the DC pulse sputter instrument. The measured and simulated results of the antenna are given. The measured peak gain of the proposed antenna is 1.66 dBi. The transparency of the IZTO/Ag/IZTO thin film on the polyimide substrate is 86%. The advantages of the proposed antenna are high transparency, low resistivity and flexibility.</P>

Effects of seasonal variations on sediment-plume streaks from dredging operations

Kim, Nam-Hoon,Pham, Van Sy,Hwang, Jin Hwan,Won, Nam Il,Ha, Ho Kyung,Im, Jungho,Kim, Youngsung Elsevier 2018 MARINE POLLUTION BULLETIN Vol.129 No.1

<P><B>Abstract</B></P> <P>When mixtures of aggregates and water dredged from the seabed are discharged at the surface into the adjacent water from a barge, coarse sediments sink immediately and fine sediments are suspended forming a plume. Recently, elongated plumes of fine sediment were observed by satellites near a dredging location on the continental shelf. Such plume streaks were longer in certain conditions with seasonality than expected or reported previously. Therefore, the present work studied the appearance of sediment plume with field measurements and numerical simulations and explains the seasonally varying restoring force and thicknesses of the surface mixed layer resulting from the vertical density distribution near the surface, along with mixing by hydrodynamic process. The resulting mixtures, after vertical restoring and mixing with the surroundings, determine the horizontal transport of suspended sediments. A numerical model successfully reproduced and explained the results from field measurements and satellite images along with the seasonal variations.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Image captured by a satellite reported the unexpectedly long streaks of sediment plume from a dredging site. </LI> <LI> Elongations of plume depend on the seasonal variations of density differences between the mixtures and surface waters. </LI> <LI> While a long streak is observed, restoring force is too weak to sink the mixtures of sediment and water to the bottom. </LI> <LI> Seasonal variations of the surface mixed layer thickness significantly affect the development of the elongated plumes. </LI> </UL> </P>

Hydrolysis of Edible Frogs (Rena dybowskii) Using Various Commercial Proteases

Youngsung Kim,Kyoungsik Kim,Taeeun Kwon 한국식품영양과학회 2017 한국식품영양과학회 학술대회발표집 Vol.2016 No.10

Is it possible to predict the neonatal rotavirus gastroenteritis by using the lymphocyte to monocyte ratio?

( Youngsung Kim ),( Ji Eun Jung ) 대한산부인과학회 2021 대한산부인과학회 학술대회 Vol.107 No.-

Study on the Development of Liquid Retort Products using Edible Frogs

Youngsung Kim,Kyoungsik Kim,Taeeun Kwon 한국식품영양학회 2016 한국식품영양학회 학술대회논문집(학술심포지움) Vol.2016 No.12

TinyOS 메시지 길이에 따른 에너지 절약 연구

김영성(Youngsung Kim),김영환(Younghwan Kim),석정봉(jungbong Suk) 한국정보과학회 2006 한국정보과학회 학술발표논문집 Vol.33 No.1

본 연구는 센서 네트워크용 운영체제인 TinyOS의 메시지 길이를 효율적으로 관리하여 저전 손실을 줄인 센서 네트워크의 연구이다. 센서 네트워크에서 가장 큰 전력 손실을 가져오는 부분은 RF통신 부분이라할 수 있다. 메시지의 길이에 따라 길이가 길면 더욱더 통신 시간이 길어지므로 전력 손실은 커질 것이다. 이와 같은 토픽에 따라 메시지의 길이를 줄여 줌으로써 RF통신에 이용되는 전력을 줄여 보고자 하는 것이다. 사용된 시뮬레이터는 TinyOS에서 자체 제공 되는 TOSSIM을 이용 하였으며 MCU가 데이터를 처리하는데 소모되는 전력과 RF 통신에 따라 소모되는 전력을 나타내었다. 시뮬레이션을 통해 메시지의 길이가 줄어들면 전력 소모가 줄어드는 것을 확인 할 수 있었다. 더 나아가 거리간의 차이에 의한 전련 소모량도 연구 되어야 할 것이다.

실시간 클라이언트-서버 DBMS에서 효율적인 트랜잭션 처리를 위한 낙관적 캐쉬 일관성 유지 및 동시성 제어

김영성(youngSung Kim),강현철(Hyunchul Kang) 한국정보과학회 1999 정보과학회논문지(B) Vol.26 No.6

클라이언트-서버 DBMS에 대한 기존의 연구는 클라이언트 데이타 캐슁이 캐쉬 일관성 유지에 드는 오버헤드에도 불구하고 시스템의 성능 향상에 유용함을 보여 주었다. 본 논문에서는 시간적 제약을 가지는 실시간 트랜잭션을 처리하는 데 있어서도 클라이언트 데이타 캐슁이 실시간 트랜잭션의 마감시간 충족률을 높이는 데 유용하다는 것을 보였다. 기존 실시간 데이타베이스 시스템에서 동시성 제어 기법과 실시간 트랜잭션 스케쥴링 기법을 통합한 것처럼, 캐쉬 일관성 유지 및 동시성 제어 기법과 실시간 트랜잭션 스케쥴링 기법을 통합한 낙관적 알고리즘을 제시하고, 클라이언트 데이타 캐슁을 지원하지 않는 경우와 그 성능을 비교하였다. 성능 평가 결과 데이타의 지역성이 낮은 작업부하에서는, 클라이언트 캐쉬의 이용으로 인해 마감시간을 어긴 실시간 트랜잭션의 비율 감소가 크지 않았지만(10% 이하), 데이타의 지역성이 높은 작업부하에서는 그 감소폭이 컸다. HOTCOLD 작업부하의 경우 클라이언트의 수가 50, 트랜잭션의 데이타 변경률이 20%일 때 마감시간을 어긴 실시간 트랜잭션의 비율이 약 47% 감소하였다. Previous works on the dent-server DBMS have shown that client data caching could enhance system performance despite the overhead of cache consistency maintenance. In this paper, we showed that client data caching is also effective in real-time transaction processing, reducing the percentage of the transactions with missed deadlines. In a real-time DBMS, the traditional concurrency control algorithms were integrated with real-time scheduling features. Similarly, the cache consistency and concurrency control scheme could be integrated with real-time scheduling features in a client-server DBMS environment. We proposed an optimistic algorithm for cache consistency and concurrency control as well as real-time scheduling, and evaluated its performance compared to the algorithm that does not support client data caching. In case of the workload with low locality of reference, the percentage of the transactions with missed deadlines was marginally reduced due to client data caching (less than 10%). However, in case of the workload with high locality of reference, the reduction was considerable. In the HOTCOLD workload, for example, the percentage of the transactions with missed deadlines was reduced by as much as 47% when the number of clients was 50 and the update ratio of transactions was 20%.

3차 저장 장치의 장착을 위한 MIDAS - II의 확장

김영성(YoungSung Kim),강현철(Hyunchul Kang),김준(June Kim) 한국정보과학회 2000 정보과학회 컴퓨팅의 실제 논문지 Vol.6 No.1

MIDAS-II는 한국전자통신연구원에서 개발한 바다 DBMS의 저장 시스템이다. 본 논문에서는, MIDAS-II가 대용량 멀티미디어 데이타 서버의 저장 시스템으로 기능하도록 광 디스크 쥬크박스 또는 테이프 라이브러리와 같은 3차 저장 장치를 효율적으로 장착하기 위한 확장에 대하여 기술하였다. 복수개의 저장 매체 (platter, 예를 들어 디스크 또는 카트리지 테이프)로 구성된 3차 저장 장치용 볼륨 구조를 위하여 기존 MIDAS-II 디스크 볼륨 구조를 확장하여 3차 저장 장치 볼륨의 용량을 Tera 바이트급으로 확대하였다. 그리고 3차 저장 장치에 저장된 LOB(Large Object) 데이타를 효율적으로 처리하기 위하여 기존 MIDAS-II LOB 구조를 확장하였다. 또한 MIDAS-II 공유 메모리 구조, 프로세스 구조, 유틸리티 등을 확장하였고, 기존 응용 프로그램 운용에 변화를 주지 않기 위하여 MIDAS-II API 함수들의 프로토타입을 그대로 유지한 채 그 내부 기능만 확장하였다. 또한 3차 저장 장치로부터의 데이타 검색 성능을 평가하여 본 논문의 3차 저장 장치 장착을 위한 MIDAS-II 확장의 적정성을 확인하였다. 이상의 확장 및 성능 평가는 모두 SunOS 5.4 환경에서 수행되었다. MIDAS-II is the storage system for BADA DBMS developed at ETRI. This paper describes the extension of MIDAS-II for incorporating the tertiary storage device such as an optical disk jukebox or a tape library, enabling MIDAS-II to function as a storage system of the data server that stores a massive amount of multimedia data. The MIDAS-II disk volume structure is extended to efficiently function as a volume for the tertiary storage device with multiple platters, which can store huge amount of data of the order of tera bytes. The storage structure of the LOB is changed to efficiently manage the LOB data in the tertiary storage device. The data structures of the shared memory, the process structure, and the utilities in MIDAS-II are also extended to efficiently incorporating the tertiary storage device. The functionalities of each MIDAS-II API function are expanded to handle the tertiary storage device, while the prototypes of those functions are intact in order not to affect the existing application programs. The performance evaluation shows that the extended MIDAS-II works effectively with the tertiary storage device. All these extensions and the performance evaluation are conducted in the SunOS 5.4 environment.

저속 압착 방식의 착즙기와 고속 파쇄 방식의 블랜더를 사용한 주스의 품질 변화에 대한 연구

김영성 ( Youngsung Kim ) 한국식품영양학회 2017 韓國食品營養學會誌 Vol.30 No.3

Vegetables and fruits contain a great deal of vitamins, minerals, dietary fiber and phytochemicals. Therefore, healthconcious consumer prefer beverage made from fresh fruits and vegetables due to their health benefits. This study was conducted to investigate differences in nutritional composition and sensory characteristics of juices depending on the apparatus used: either a low-speed juicer or high-speed blender. All ingredients could be made into juice without addition of water using the low speed juicer. However, addition of water was necessary to produce juice with the high-speed blender. Phenol and flavonoid content, were higher in juice made with the low-speed juicer than that produced with the high-speed blender and were correlated with DPPH radical scavenging ability. Protease activity of pineapples juices was not significantly different for the two methods, but protease activity of kiwi juice was about 8 times higher in juice made with low-speed juicer than that made with the high-speed blender. SOD activity also tended to be higher in the juice made with low-speed juicer. The concentration of dissolved oxygen in the juice made with high-speed blender was higher than that of juice made with a low-speed juicer and was correlated with color change. In addition, the high-speed blender caused an increase juice temperature, but temperature was not changed during use of the low-speed juicer. The noise level of the low-speed juicer was low, but the high-speed blender had high noise intensity comparable to that of railway or aircraft noise. In the sensory evaluation of juice, juice made with the low-speed juicer was preferred over juice made with the high-speed blender. As a result, the overall quality of the juice produced using the low-speed juicer was superior.