• 분석과학
• /
• 제25권6호
• /
• pp.339-344
• /
• 2012

In this research, hydride generation in HPLC-ICPMS for the selenium speciation was investigated. Chemical and photochemical vapor generation techniques were compared for the effective generation of selenium vapour. $HBr/KBrO_3$ was used for the chemical reduction and a UV lamp was used for the photochemical reduction. It was found out that the photochemical reduction was more effective than the chemical reduction in all of selenium species studied. The optimum conditions for the generation of vapour are 0.4% KI, 2.5% $NaBH_4$, and 1.0 M HCl. The enhancement factor using a photochemical hydride generation was from 6.3 to 16.7 times for inorganic and organic selenium species.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• 제4권2호
• /
• pp.193-198
• /
• 2004

This paper describes an automatic finite element (FE) mesh generation for three-dimensional structures consisting of tree-form surfaces. This mesh generation process consists of three subprocesses: (a) definition of geometric model, (b) generation of nodes, and (c) generation of elements. One of commercial solid modelers is employed for three-dimensional solid structures. Node is generated if its distance from existing node points is similar to the node spacing function at the point. The node spacing function is well controlled by the fuzzy knowledge processing. The Voronoi diagram method is introduced as a basic tool for element generation. Automatic generation of FE meshes for three-dimensional solid structures holds great benefits for analyses. Practical performances of the present system are demonstrated through several mesh generations for three-dimensional complex geometry.

• Wind and Structures
• /
• 제32권4호
• /
• pp.321-340
• /
• 2021

In 2019, 5.6% of the total energy produced worldwide came from wind. Offshore wind generation is still a small portion of the total wind generation, yet its growth is exponential. Higher availability of sites, larger producibility and potentially lower environmental impacts make offshore wind generation attractive. On the other hand, as the water depth increases, fixed foundations are no more viable, and the new frontier is that of floating foundations. This paper brings an overview of why and how offshore wind energy should move deep water; it contains material from the Keynote Lecture given by the first author at the ACEM20/Structures20 Conference, held in Seoul in August 2020. The paper is organized into four sections: the first giving general concepts about wind generation especially offshore, the second and the third considering economic and technical aspects, respectively, of offshore deep-water wind generation, in the fourth, some challenges of floating offshore wind generation are presented and some conclusions are drawn.

• 한국전자거래학회지
• /
• 제17권2호
• /
• pp.63-72
• /
• 2012

2000년대 초반부터 한국의 이동통신시장은 급속하게 팽창해 왔으며, 최근 들어 그 성장 속도가 둔화되고 있으나 성장은 계속 진행 중에 있다. 이와 같은 환경에서 4세대 이동통신 서비스가 2011년 10월부터 시작되어 3세대 서비스와 4세대 서비스가 함께 존재하고 이를 통해 이동통신시장의 경쟁구도가 더욱 복잡하고 치열한 상황이 되었다. 본 연구는 다세대 확산 모형을 활용하여 3세대 및 4세대 이동통신 서비스 가입자 규모를 예측하는데 목적이 있다. 이를 위해 세 개의 파라미터, 즉 Norton and Bass 모형[11]에서 사용되는 혁신계수, 모방계수 및 포화수준계수의 값을 추정하기 위해 3세대에서 4세대로 대체되는 서비스 대체의 유사 사례를 역추적하는 방법을 사용하였다. 시뮬레이션 결과, 다세대 확산모형과 유사사례 추론을 통해 신규서비스인 4세대 이동통신서비스 시장규모를 성공적으로 예측할 수 있었다는 결론을 얻었다.

• 한국응용곤충학회지
• /
• 제16권1호
• /
• pp.13-19
• /
• 1977

줄무늬 잎마름병의 매개와 직접 관계가 있는 월동세대부터 제3세대까지의 애멸구의 세대별 증식상황을 기주식물의 종류 및 생육상태와 관련시켜 Pot시험과 유균사육을 하여 다으과 같은 결과를 얻었다. 1. 월동세대, 맥류에서 우화한 제1세대, 벼에서의 제2세대 성충의 평균 수명은 13.4일, 12.9일, 10.2일로 사료교환시의 간섭으로 정상성충의 수명에 비하여 짧아졌으나 세대별 차는 적은 것으로 생각된다. 2. 월동세대, 제1세대, 그리고 제2세대 성충의 유묘상에서의 평균산란수는 각각 131.3, 124.9 그리고 142.3으로 큰 차가 없었으며 대체로 3주 이내에 전체의 $90\%$ 이상이 산란되었다. 3. 부화율은 유묘상에서 제1세대가 $77.4\%$, 제2세대가 $93.1\%$였으나 pot 실험에서 정추란수에 의한 부화율은 제1세대 $67.5\%$, 제2세대 $84.1\%$ 제3세대 $21.9\%$ 등으로 현저한 차가 있으며 보리에서 5월 17일 늦게 접종한 것에서는 란수에는 큰 차가 없었으나 부화율은 $13.5\%$로 5월 1일 이전 접종시의 $67.5\%$에 비하여 극히 낮았다. 4. 약충기간은 제1세대 19.4일, 제2세대 13.3일이었고 약충기간중의 치사율은 기주식물의 생육상태에 따라 차가 있는 듯 하였다. 5. Pot시험에서의 평균우화수는 제1세대 $37.2\%$, 제2세대 $55.3\%$, 제3세대 $11.6\%$으로 세대간차가 심하였으며 보리에서 5월 17일 접종구의 평균성충수가 $7.4\%$였음을 생각할 때 기주의 생리적 조건과 밀접한 관계가 있는 것으로 생각된다. 6. 이상으로 보아 애멸구의 선천적 증식능에는 세대간차가 없는 것으로 생각되며 기주의 생리적 조건은 기상적 조건이나 천적과 아울러 밀도변동에 밀접한 관계가 있으며 애멸구의 강한 이동성도 이와 같은 점과 유관한 것으로 추측된다.

• 디지털산업정보학회논문지
• /
• 제18권4호
• /
• pp.111-122
• /
• 2022

Many companies are now studying these generational conflict issues and seeking countermeasures. As seen in the recent performance-based pay issue, the MZ generation is boldly showing their intention unlike the previous generation. This study focuses on LX Hausys' education program to overcome the generation gap. As a representative field education program of LXHausys, it is a longevity education program that was developed and operated at the end of 14 years and has been in operation so far. By acknowledging and understanding the generation gap through this educational program, it was possible to see that they could sympathize and accept each other one step further, and that trust in each other was formed on the basis of it. The success factors of the generation empathy program were identified as the willingness to share perceptions between labor and management, participatory education programs, active participation of members, and overcoming generation empathy. Through such education, the organization should continuously raise the issue of generational empathy and allow members to recognize it as an object to overcome. To this end, efforts should be made to overcome generational differences.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2000년도 추계종합학술대회
• /
• pp.207-211
• /
• 2000

다양한 종류의 데이터 서비스를 다양한 무선환경에서 다양한 요구품질을 만족시키면서 제공하는 이동통신 기술이라면 일차적으로는 제4세대 이동통신기술로 분류할 수 있다. 4세대 이동통신기술은 이동통신 시스템을 구성하는 각각의 구성 요소들이 현재까지의 제 2세대 및 현재 개발중인 제3세대 이동통신 기술과는 차별화 된 형태를 가져야 하며 3세대까지의 이동통신 기술에 비하여 보다 발전적이고 통합적인 형태를 띠어야 할 것이다 제4세대 이동통신의 핵심기술은 다음과 같은 기술을 포함하고 있다. Adaptive coding and modulation, Smart antenna, Interference cancellation, mechanism between various networks 본 논문에서는 이와 같은 기술들의 개발현황 및 표준화 현황에 대해 기술하고자 한다.

• 진공이야기
• /
• 제4권4호
• /
• pp.14-17
• /
• 2017

Recently, quantum-dots light emitting diodes (QLEDs) are considered as a next-generation display due to the superior luminescence behaviors, photo stability and narrow spectral emission bandwidth. Moreover, the emission color of QLEDs can be easily controlled by changing the dimension of quantum dots (QDs). A flexible display based on QLEDs can be achieved using low-cost solution process, such as a printing technology. Therefore, QLEDs are expected as a next generation display. In this document, recent progresses in QDs technology will be introduced.

• Tribology and Lubricants
• /
• 제13권4호
• /
• pp.26-32
• /
• 1997

The heat generation of the angular contact and the deep groove ball bearing is studied experimentally and numerically. The temperature variation of the inner and outer races and the temperature increase distribution are measured for the shaft rotational speeds, preloads, viscosities of the lubricant and lubrication methods. The measured temperature distributions are used as the input data of the numerical simulation to estimate the heat generation rate at the bearing. The temperatures of the inner and outer race increase more rapidly and approach faster to their steady values as the rotational speed increases. The optimal viscosity of the oil to minimize the heat generation is 8~10 cSt at 4$0^{\circ}C$ when the oil-air lubrication method is adopted. The heat generation of the bearing increases with the rotational speed and depends more on the lubrication method than on the preload variation.

• 로봇학회논문지
• /
• 제4권1호
• /
• pp.56-61
• /
• 2009

A probability-based data generation is a typical context-generation method that is a not only simple and strong data generation method but also easy to update generation conditions. However, the probability-based context-generation method has been found its natural-born ambiguousness and confliction problems in generated context data. In order to compensate for the disadvantages of the probabilistic random data generation method, a situation propagation network is proposed in this paper. The situation propagating network is designed to update parameters of probability functions are included in probability-based data generation model. The proposed probability-based context-generation model generates two kinds of contexts: one is related to independent contexts, and the other is related to conditional contexts. The results of the proposed model are compared with the results of the probabilitybased model with respect to performance, reduction of ambiguity, and confliction.