• 자원ㆍ환경경제연구
• /
• 제27권3호
• /
• pp.463-493
• /
• 2018

우리나라의 인구구조는 1인 가구 및 고령가구가 점차 증가하는 형태로 변화하고 있으며, 이는 국내 에너지 수요에 영향을 미칠 가능성이 있다. 이 연구를 통해 1인 및 고령가구의 에너지 소비패턴이 일반 가구의 에너지 소비패턴과 구별되는 특징이 존재하는지를 분석함으로써 인구구조 변화에 따른 에너지 소비 특성을 살펴보고자 하였다. 지역고정효과 모형과 에너지 경제연구원의 가구상설표본조사 패널 자료(2013-2015년)를 실증분석에 활용하였다. 1인 가구는 다른 가구 형태에 비해 모든 에너지원에서 소비가 많은 것으로 나타났으며, 특히 1인 가구 중 4060대의 소비가 가장 많았다. 고령화 효과는 에너지원에 따라 상이하게 나타났다. 고령가구의 전력 소비는 다른 연령대에 비해 대체로 많거나 비슷하였으나, 등유는 고령가구의 소비가 가장 적었다. 반면, 가스 및 총에너지는 연령에 따른 차이가 존재하지 않았다. 연구결과는 정부가 1인 가구 및 고령화로 인해 증가하는 전력 혹은 에너지 소비 추이를 면밀히 관찰하면서 이에 대응하기 위한 다양한 정책 방안을 마련할 필요가 있음을 시사한다.

• Journal of Mechanical Science and Technology
• /
• 제18권10호
• /
• pp.1700-1711
• /
• 2004

Piston friction is one of the important but complicated sources of energy loss of a hydraulic axial piston machine. In this paper, two formulas are derived for estimating instantaneous piston friction force and average piston friction moment loss. The derived formula can be applicable for piston guides with or without bushing as well as for axial piston machines of motoring and pumping operations. Through the formula derivation, a typical curve shape of friction force found from several experimental measurements during one revolution of a machine is clearly explained in this paper that it is mainly due to the equivalent friction coefficient dependent on its angular position. Stribeck curve effect can easily be incorporated into the formula by replacing outer and inner friction coefficients at both edges of a piston with the coefficient given by Manring (1999) considering mixed/boundary lubrication effects. Novel feature of the derived formula is that it is represented only by physical dimensions of a machine, hence it allows to estimate the piston friction force and loss moment of a machine without hardworking experimental test.

• 기본간호학회지
• /
• 제12권3호
• /
• pp.404-412
• /
• 2005

Purpose: This study was done to examine the correlations between personality type and job satisfaction of nurses. Methods: Subjects included three hundred twelve nurses ages from 21 to 55. The Myers-Briggs Type Indicator(MBTI) was administered to determine the personality types of the nurses(n=312). A job satisfaction survey including a demographic and career questionnaire was also used. Data were analyzed using ANOVA. Results: The mean score fur job satisfaction was 113.68 out of 205. The result showed that there was no statistically significant correlation between job satisfaction and information gathering functions, S: Sensing, N: Intuition (t=.667, p=.499), T; Thinking, F; Feeling (t=.822, p=.412). The results, however, indicated that style for gaining energy(I: Introversion, E: Extroversion)(t=2.008, p=.046) and life dealing style(J : Judgement, P : Perception)(t=2.290, p=.023) were significantly correlated with job satisfaction. The extrovert focuses on the outside and get energy through interacting with people and doing things. Judgement type is described as organized, decisive, and orderly. Conclusion: Nurses in the extrovert and judgement types were more satisfied with their Jobs than those in the introvert and perceptive type. Other results support that educational level, marital status, job characteristics, clinical experiences, motivation for nursing, and night duty were correlated with job satisfaction.

• Nuclear Engineering and Technology
• /
• 제53권10호
• /
• pp.3275-3285
• /
• 2021

A Nuclear Power Plant (NPP) is a complex dynamic system-of-systems with highly nonlinear behaviors. In order to control the plant operation under both normal and abnormal conditions, the different systems in NPPs (e.g., the reactor core components, primary and secondary coolant systems) are usually monitored continuously, resulting in very large amounts of data. This situation makes it possible to integrate relevant qualitative and quantitative knowledge with artificial intelligence techniques to provide faster and more accurate behavior predictions, leading to more rapid decisions, based on actual NPP operation data. Data-driven models (DDM) rely on artificial intelligence to learn autonomously based on patterns in data, and they represent alternatives to physics-based models that typically require significant computational resources and might not fully represent the actual operation conditions of an NPP. In this study, a feed-forward backpropagation artificial neural network (ANN) model was trained to simulate the interaction between the reactor core and the primary and secondary coolant systems in a pressurized water reactor. The transients used for model training included perturbations in reactivity, steam valve coefficient, reactor core inlet temperature, and steam generator inlet temperature. Uncertainties of the plant physical parameters and operating conditions were also incorporated in these transients. Eight training functions were adopted during the training stage to develop the most efficient network. The developed ANN model predictions were subsequently tested successfully considering different new transients. Overall, through prompt prediction of NPP behavior under different transients, the study aims at demonstrating the potential of artificial intelligence to empower rapid emergency response planning and risk mitigation strategies.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
• /
• pp.421-421
• /
• 2006

The light and energy-efficiency of classical liquid crystal displays is notoriously poor due to the use of absorption-based linear polarisers and colour filters. For instance, the light efficiency of PVAL polarisers is typically between 40 and 45 % and the colour filters have a typical efficiency below 35 % which results in a total light and energy-efficiency of the display below 10 %. In the past, a variety of polarizers were developed with an enhanced efficiency in generating linearly polarized light. Typically, these polarizers are based on the polarisationselective reflection, scattering or refraction of light i.e. one polarisation direction of light is directly transmitted to the LCD/viewer and the other polarization direction of light is depolarised and recycled which results in a typical efficiency for generating linearly polarized light of 70-85 %. Also, special colour filters have been proposed based on chiral-nematic reactive mesogens which increase the efficiency of generating colour. Despite the enormous progress in this field, a need persists for improved methods for generating polarized light and colour based on low cost optical components with a high efficiency. Here, the use of holographic phase gratings is reported for the generation of polarized light and colour. The phase grating are recorded in a photopolymer which is coated onto a backor frontlight for LCDs. Typically the recording is performed in the transmisson mode or in the waveguiding mode and slanted phase gratings are generated with their refractive index modulation at an angle between 20o and 45o with the normal of the substrate. It is shown that phase gratings with a high refractive index modulation and a high efficiency can be generated by a proper selection of the photopolymer and illumination conditions. These phase gratings coupleout linearly polarized light with a high contrast (> 100) and the light is directed directly to the LCD/viewer without the need for redirection foils. Dependent on the type of phase grating, the different colours are coupled-out at a slightly different angle which potentially increases the efficiency of classical colour filters. Moreover, the phase gratings are completely transparent in direct view which opens the possibility to use them in frontlights for LCDs. Holographic polarization gratings posses a periodic pattern in the polarization state of light (and not in the intensity of light). A periodic pattern in the polarization direction of linearly polarized light is obtained upon interference of two circularly polarized laser beams. In the second part of the lecture, it is shown that these periodic polarization patterns can be recorded in a linear photo-polymerizable polymer (LPP) and that such an alignment layer induces a period rotation in the director of (reactive and non-reactive) liquid crystals. By a proper design, optical components can be produced with only first order diffraction and with a very high efficiency (>0.98). It is shown that these diffraction gratings are potentially useful in projection displays with a high brightness and energy efficiency

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
• /
• pp.52-55
• /
• 2006

It's used to be said that tsunami is a rare event. The recurrence time of tsunami in Sumatra area is approximately 230 years as CalTech Research Group‘s study from paleocoral. However, the tsunami occurred in Indian Ocean on 26 December 2004, 28 March 2005 and 17 July 2006, because the earthquakes still release the energy. To cope with the tsunami disaster, we have to put the much effort on better disaster preparedness. The Tsunami Reduction Of Impacts through three Key Actions (TROIKA) was suggested by Eddie N. Bernard, the director of NOAA/PMEL (Pacific Marine Environmental Laboratory). They are Hazard Assessment, Mitigation and Warning Guidance. The satellite remote sensing has potential on these actions. The medium and high resolution satellite data were used to assess the degree of damage at the six-damaged provinces on the Andaman seacoast of Thailand. Fast and reliable interpretation of the damage by remote sensing method can be used for inundation mapping, rehabilitation and housing plans for the victims. For tsunami mitigation, the satellite data can be used with GIS to construct the evacuation map (evacuation route and refuge site) and coastal zone management. It is also helpful for educational program for local residents and school systems. Tsunami is a kind of ocean wave, therefore any satellite sensors such as SAR, Altimeter, MODIS, Landsat, SPOT, IKONOS can detect the tsunami wave in 2004. The satellite images have shown the characteristics of tsunami wave approaching the coast. For warning, satellite data has potential for early warning to detect the tsunami wave in deep ocean, if there are enough satellite constellation to monitor and detect the first tsunami wave like the pressure gauge, seismograph and tide gauge with the DART buoy can do. Moreover, the new methods should be developed to analyse the satellite data more faster for early warning procedure.

• 한국환경복원기술학회지
• /
• 제13권2호
• /
• pp.124-137
• /
• 2010

This study was started with the objective of restoring abandoned embanked farms, which are recently increasing, to mud flat by putting in least amount of energy in the aspect of environmental restoration. For the direction and establishment of the proposal for the restoration of mud flat using embanked farms, a case of Maipo Wetland in Hongkong was analyzed, and a proposal was prepared considering the condition of mud flat in Gochang. The restoration of mud flat in Gochang is intended to create various wetland ecological spaces as well as to provide opportunities for experience, education, recreation, and tourism. Effort was made to development an environment closest to the local ecological environment considering the shape and topographical condition of existing abandoned farms. For construction of the habitat, a target species was chosen and the plan for selection, planting, and management of species of trees suitable for the target species was established. In addition, the water level will be controlled by water gates to conform to the resting, spawning, breeding, and migration period considering the behavioral pattern of waders, the target species. The research on the restoration of mud flat in Korea is in incipient stage and this study provided an opportunity to review the possibility of restoration of abandoned embanked farms to mud flat. For the success of mud flat restoration from a long-term perspective, development of acclimating design infrastructure, technology improvement for mud flat restoration, and basis of partnership for the maintenance should be prepared in a systematical way.

• 대한인간공학회지
• /
• 제34권1호
• /
• pp.29-43
• /
• 2015

Objective: The aim of this study is to develop management guidelines and a procedure for an anthropometric suitability assessment of the main control room (MCR) in nuclear power plants (NPPs). Background: The condition of the MCR should be suitable for the work crews in NPPs. The suitability of the MCR depends closely on the anthropometric dimensions and ergonomic factors of the users. In particular, the MCR workspace design in NPPs is important due to the close relationship with operating crews and their work failures. Many documents and criteria have recommended that anthropometry dimensions and their studies are one of the foremost processes of the MCR design in NPPs. If these factors are not properly considered, users can feel burdened about their work and the human errors that might occur. Method: The procedure for the anthropometric suitability assessment consists of 5 phases: 1) selection of the anthropometric suitability evaluation dimensions, 2) establishment of a measurement method according to the evaluation dimensions, 3) establishment of criteria for suitability evaluation dimensions, 4) establishment of rating scale and improvement methods according to the evaluation dimensions, and 5) assessment of the final grade for evaluation dimensions. The management guidelines for an anthropometric suitability assessment were completed using 10 factors: 1) director, 2) subject, 3) evaluation period, 4) measurement method and criteria, 5) selection of equipment, 6) measurement and evaluation, 7) suitability evaluation, 8) data sharing, 9) data storage, and 10) management according to the suitability grade. Results: We propose a set of 17 anthropometric dimensions for the size, cognition/perception action/behavior, and their relationships with human errors regarding the MCR design variables through a case study. The 17 selected dimensions are height, sitting height, eye height from floor, eye height above seat, arm length, functional reach, extended functional reach, radius reach, visual field, peripheral perception, hyperopia/myopia/astigmatism, color blindness, auditory acuity, finger dexterity, hand function, body angle, and manual muscle test. We proposed criteria on these 17 anthropometric dimensions for a suitability evaluation and suggested an improvement method according to the evaluation dimensions. Conclusion: The results of this study can improve the human performance of the crew in an MCR. These management guidelines and a procedure for an anthropometric suitability assessment will be able to prevent human errors due to inadequate anthropometric dimensions. Application: The proposed set of anthropometric dimensions can be integrated into a managerial index for the anthropometric suitability of the operating crews for more careful countermeasures to human errors in NPPs.

• 대한지역사회영양학회지
• /
• 제20권5호
• /
• pp.327-337
• /
• 2015

Objectives: Dietary life is closely associated with dietary attitude and diet-related knowledge. Particularly, dietary habit such as sodium intake can be affected by various dietary behaviors such as food choices, dietary attitude toward salty food and a preference for salty taste. The purpose of this study was to assess sodium-related nutrition knowledge and to identify sodium-related attitude and behaviors according to the level of sodium-related knowledge of university students. Methods: Anthropometric measurements were provided by 408 students who participated in this study. The study participants answered questionnaires to provide information on general dietary behaviors, sodium-related dietary attitude and other behavioral factors. A total score of nutrition knowledge was used to categorize study participants in to two groups, namely, low level in sodium-related knowledge (LNaK) or high level in sodium-related knowledge (HNaK) and the attitude and the behaviors of students toward sodium intake were compared between these two groups. Results: The ratio of female students in HNaK group was higher than that in the LNaK group. HNaK group had a higher score in checking nutrition label of processed food than the LNaK group. Total score of sodium-related attitude and behaviors of HNaK group were 34.81 and 32.75, respectively and these scores were significantly higher than that of the LNaK group whose scores were 32.57 and 30.57, respectively. Total energy intake was not different between two groups but the intakes of calcium, vitamin B2 and folate were higher in HNaK group than in the LNaK group. Correlation analysis adjusted for age and gender revealed that total score of sodium-related nutrition knowledge was positively correlated with total score of sodium-related attitude and behaviors. Conclusions: In conclusion, students who had high level of sodium-related nutrition knowledge had desirable attitude and behaviors toward sodium intake and these results can be considered in nutrition education for university students.

• 한국가스학회지
• /
• 제14권3호
• /
• pp.26-34
• /
• 2010

한국가스공사는 1983년 가스의 안정적인 공급을 위해 특별법에 의거 설립되었으며 30개 지역의 가스소매를 담당하는 도시가스회사에 천연가스 도매공급을 전담하고 있다. 가스공사가 수입하는 가스의 측정방식은 LNG 하역 전후의 수송선 액위를 측정함으로써 계량한다. 이때 가스성분분석은 수입가스의 가격이 열량에 의해 산정되기 때문에 필수적이다. 또한 터빈미터는 도시가스사로 공급하는 가스의 계량에 널리 쓰이고 있다. 그러나 발전용으로 공급되는 가스의 계량설비와는 달리 도시가스사로 공급되는 가스를 계량하는 설비에는 가스요금이 열량에 의해서가 아니라 부피에 의해서 부과되기 때문에 가스성분을 측정하는 분석기가 없다. 따라서 도시가스사가 가스공사로부터 구입하는 가스양과 소비자에게 판매하는 가스양이 일치하지 않는 문제점이 발생한다. 그 이유는 소매용 가스미터에 내재하는 오차와 운용상의 문제로 인해 도매용 계량설비와 소매용 가스미터의 수치에는 차이가 있기 때문이다. 본 논문에서는 도시가스사와 일반 소비자 간의 실제 가스양에 대한 논쟁에 관해 조사하였으며 가스 계량오차에 관한 문제점을 해소하기 위한 바람직한 기술적, 경제적 정책방향을 제안하는데 중점을 두었다.