Jung Sook Oh

This paper described the general concept of combustion instability and its mechanism in gas turbine engines. The approaching method to study this phenomenon was introduced including the up-to-date research activity in the world. Combustion instability is one of critical problems, still now, affecting engine performance, durability and operation. In addition it is known that this problem is caused by coupling between fuel or air flow fluctuation and heat release rate in gas turbine engines, which

카카오톡 가입자 수가 1억 명(2013년 7월)을 돌파하며 급속한 성장세를 보이고 있다. 카카오톡이 많은 사람들의 일상생활에서 필수품으로 자리 잡자 카카오톡에 대한 연구도 활발해지고 있다. 하지만 기존 연구에서는 플랫폼으로서의 카카오톡에 대한 분석, 다시 말해 주식회사 카카오의 플랫폼 전략에 대한 분석이 충실하게 이뤄지지 않았다. 본 연구는 플랫폼 전략에 대한 대표적인 연구인 Platform Leadership(Gawer & Cusumano, 2002; 2008)과 Winner-take-all dynamics(Eisenmann et al, 2006), Open Service Innovation(Chesbrough, 2011)의 논의 내용을 이론적 배경으로 삼아, 주식회사 카카오의 플랫폼 전략을 분석했다. 분석 결과 카카오가 경쟁자인 다음커뮤니케이션의 마이피플과 네이버의 라인을 제친 것은 Eisenmann et al(2006)의 승자독식 플랫폼의 조건으로 설명됐다. 이렇게 경쟁자들을

In a two-phase operation, E. coli containing λSNU1 (Q-S-) in the chromosome is typically cultured at 33℃ and cloned gene expression is induced by elevating the temperature. At least 40℃ is necessary for complete induction of cloned gene expression; however, temperatures above 40℃ have been shown to inhibit cloned gene expression. This suggests that a three-phase operation, which has an induction phase between the growth and production phases, may result in higher gene expression. In this study,

다양한 서비스들의 조합인 컨버전스 서비스의 중요성이 날로 커지고 있다. 본 연구는컨버전스 서비스 사례 중 하나인 텔레매틱스 서비스를 정보서비스, 엔터테인먼트 서비스로분류하고 이들의 만족도와 디자인, 가격 요인이 기술수용 모형의 요인인 인지된 용이성, 인지된유용성 및 구매의도와 어떤 관계를 이루는지를 실증하였다. 구조방정식을 통해 요인들간의경로를 분석한 결과 서비스의 만족, 디자인 요소가 인지된 유용성에는 유의한 영향을 미치지못하고, 인지된 용이성에만 영향을 미치는 것으로 나타났다. 이는 운전 중에 사용하는 텔레매틱스서비스 특징상 고객들이 이용하기에 쉬운 것이 강조되어야 함을 의미한다.

DLN-2.6 combustion tuning was carried out for the maintenance of GE 7FA+e gas turbine at Seo-Incheon combined cycle power plant. DLN-2.6 combustion system has the higher level of yellow plume and combustion vibration problem in the initial operating mode than that of the base mode(100~160 MW). The objectives of this study are to investigate the causes of yellow plume and combustion vibration problems at the starting mode and to suggest the best operating condition for the reliable working of the

Combustion vibration and yellow plume are frequently occurred during an initial operating mode in GE 7FA+e DLN-2.6 combustors which are running at Seo-Inchon combined cycle power plant. The objectives of this paper are to analyze the causes of those two phenomena and to study non-dimensional factors to design a lab scale dump combustor. With the consideration of real combustor, the peak frequencies of vibration is 120~140 Hz due to cold flow in plenum. This plenum is considered as a major parame

Recently in Korea, ‘win-win management(Sangsaeng management)’ is receiving much attention. In many cases, small and mid-sized suppliers get one directional help from buyers who are usually larger companies. Buyers who have advanced technology and better financial position provide funding at a lower cost and opportunities for better skills. This may not correspond to the true meaning of ‘Sangsaeng management’ because it is just one-way cooperation. This paper focuses on active, bi-directional coo

Due to rapid developments of IT technologies, convergence services like IPTV (Internet protocol television) are shown up. Even though expert and customer had great expectations for this innovative service, commercialization was delayed for years by the legal dispute between industry players. One of the biggest problems was that whether internet backbone providers have to share their internet network backbone with IPTV service providers (which don’t have network backbone) or not. As other countri

The effects of acoustic excitation of coaxial air on mixing enhancement and reduction of nitrogen oxides (NOx) emission were investigated. A compression driver was attached to the coaxial air supply tube to impose excitation. Measurements of NOx emission with frequency sweeping were performed to observe the trend of NOx emission according to the fuel and air flow conditions and to inquire about the effective excitation frequency for reducing NOx. Then, Schlieren photographs were taken to visuali

Social networking services (SNSs) serve to strengthen people’s social relationships by providing ways for people to utilize such relationships especially like workplace. With the development of the internet worldwide, the number of SNS users is rapidly growing and a wider range of service types have become available. In this study, we designed a research model with a focus on what makes people use SNSs at workplace and how it is associated with changes in relationship quality and their intention

The study of nitrogen dilution effect on the flame stability was experimentally investigated in a non-premixed turbulent lifted hydrogen jet with coaxial air. Hydrogen gas was used as a fuel and coaxial air was used to make flame liftoff. Each of hydrogen and air were injected through axisymetric inner and outer nozzles (dF=3.65 mm and dA=14.1 mm). And both fuel jet and coaxial air velocity were fixed as uF=200 m/s and uA=16 m/s, while the mole fraction of nitrogen diluents gas was varied from 0

Artificial Intelligence (AI), especially in the domain of text-generative services, has witnessed a significant surge, with forecasts indicating the AI-as-a-Service (AIaaS) market reaching a valuation of $55.0 Billion by 2028. This research set out to explore the quality dimensions characterizing synthetic text media software, with a focus on four key players in the industry: ChatGPT, Writesonic, Jasper, and Anyword. Drawing from a comprehensive dataset of over 4,000 reviews sourced from a softw

With a prospective of rapid deployment of IOT, a systematic approach to derive a business strategy for various possible scenarios of IOT applications is in great demand. In this paper, a conceptual framework that can be utilized for the purpose of assessing the market potential and of setting up an initial business strategy for IOT deployment is suggested. The framework consists of utilization of well-known value curve analysis, ecosystem analysis and house of quality tools. The value curve anal

It was experimentally studied that the stabilization mechanism of turbulent, lifted jet flames in a non-premixed condition to reveal the newly found liftoff height behavior of hydrogen jet. The objectives are to report the phenomenon of a liftoff height decreasing as increasing fuel velocity, to analyse the flame structure and behavior of the lifted jet, and to explain the mechanisms of flame stability in hydrogen turbulent non-premixed jet flames. The hydrogen jet velocity was changed from 100