• 한국태양에너지학회:학술대회논문집
• /
• 2008.04a
• /
• pp.154-159
• /
• 2008

Daylight is an important component for human and energy saving. Also, available daylight in inside provides positive influence on psychological and physiological aspects as well as good visual environment. It is important to lighting design for office building not only designing for artificial lighting but also using daylight for energy savings. Therefore, lighting designers and architectures must consider the effects of the daylight for human environment and energy savings. The BIN Method is one of the methods to predict energy savings using computer simulation but it spends more time than expectation. So, this study performs to simulate a simple space using the RADIANCE for examination and simplification of the BIN Method.

• Proceedings of the SAREK Conference
• /
• 2008.06a
• /
• pp.243-248
• /
• 2008

The purpose of this study is to introduce alternative cost-effectiveness analysis method of DSM investment programs. This alternative method is Value Test method which consider the effects of DSM investment program on customer value. And this method was applied for actual DSM investment program in natural gas domain. By utilize this method to evaluate cost-effectiveness of DSM investment programs, it is expected to make right decision to enforce and complement those programs.

• Journal of the Society of Naval Architects of Korea
• /
• v.53 no.1
• /
• pp.62-68
• /
• 2016

A simple calculation tool for added resistance in waves is developed to utilize for initial design or embedded module for navigation support system. In order to select an appropriate calculation method for added resistance in waves, three methods (drift method, integrated pressure method, radiated energy method) based on strip method are applied to Wigley I and KVLCC2. The methods for added resistance in waves give the underestimated results because it is difficult to consider nonlinear effects due to reflected wave. We apply asymptotic (Faltinsen's method) and empirical formula (NMRI's method) to improve the accuracy for short wave length region. In comparison with experimental results, the combination of radiated energy method and short wave correction method of NMRI is the most reasonable. However, a simple sum of results calculated by two methods gives rise to the overestimation of added resistance for short wave length region because added resistance of radiated energy method exits in total reflection region. To overcome this problem, modified radiated energy method is proposed using correction coefficient defined by reflection coefficient of NMRI's method. Finally, added resistance in regular waves is composed of added resistance of modified radiated energy method and that of short wave correction method of NMRI. Estimated added resistance in regular waves is validated by comparison with experimental results of other research groups.

• Proceedings of the KIEE Conference
• /
• 2000.11a
• /
• pp.58-60
• /
• 2000

In this paper we present an estimation method of electric energy[kWh] for load management of pole-transformer. For the electric energy estimation, we use the nonlinear load research based estimation(NLRE) algorithm. The NLRE curve is the normalized annual cumulative energy consumption for a particular day in a year. And, it is used for the coefficient estimation. Estimation method of suggested electric energy of pole-transformer used billing cycle electric energy estimation equation is verified as comparison billing cycle electric energy and estimated electric energy. We can reduce the error of peak load estimation by suggested method than the conventional method in domestic.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1997.10a
• /
• pp.19-24
• /
• 1997

In this study, we extend the application of the interface-matrix(IM) method for reflector modeling to Analytic Flux Expansion Nodal (AFEN) method. This include the modifications of the surface-averaged net current continuity and the net leakage balance conditions for IM method in accordance with AFEN fomular. AFEN-interface matrix (AFEN-IM) method has been tested against ZION-1 benchmark problem. The numerical result AFEN-IM method shows 1.24% of maximum error and 0.42% of root-mean square error in assembly power distribution, and 0.006%Δk of neutron multiplication factor. This result proves that the interface-matrix method for reflector modeling can be useful in AFEN method.

• Hwankyungkyoyuk
• /
• v.19 no.3
• /
• pp.102-113
• /
• 2006

The purpose of this study is to devise proper plans for sustainable energy management in schools through applying school eco-audit to energy field. This study is performed by literature review and the analysis of case study. This study analyzes the energy-saving model school according to the three cores of eco-audit such as school administration system, teaching-learning method, and ecological policy, and the result of the study is as followings. First, according to the analysis of school administration system for energy education programs, the participation of all the school staff is very low, and the democratic decision-making system is unsatisfactory. Second, according to the analysis of teaching-learning method, the program is mainly managed by teacher-oriented method not by learner-oriented one. The effect on the education of energy-saving program is a little improved in cognitive area, but is insufficient in affective area. Third, in the aspect of the ecological policy, the practical energy-saving effect in schools is unsatisfactory, and shows the difficulty of continuing application of the program. Consequently, it is desirable to integrate the energy-saving program with the eco-audit for sustainable energy management in schools. Implementation of the energy eco-audit in schools for the sustainable development education as teaching-learning method could achieve extended effect for the earth environmental conservation.

• ETRI Journal
• /
• v.43 no.2
• /
• pp.221-231
• /
• 2021

To resolve energy depletion issues in massive Internet of Things sensor networks, we developed a set of distributed energy beamforming methods with one-bit feedback and clustering for multi-node wireless energy transfer, where multiple singleantenna distributed energy transmitters (Txs) transfer their energy to multiple nodes wirelessly. Unlike previous works focusing on distributed information beamforming using a single energy receiver (Rx) node, we developed a distributed energy beamforming method for multiple Rx nodes. Additionally, we propose two clustering methods in which each Tx node chooses a suitable Rx node. Furthermore, we propose a fast distributed beamforming method based on Tx sub-clustering. Through computer simulations, we demonstrate that the proposed distributed beamforming method makes it possible to transfer wireless energy to massive numbers of sensors effectively and rapidly with small implementation complexity. We also analyze the energy harvesting outage probability of the proposed beamforming method, which provides insights into the design of wireless energy transfer networks with distributed beamforming.

• Transactions on Electrical and Electronic Materials
• /
• v.4 no.5
• /
• pp.28-32
• /
• 2003

Europium-doped gadolinium oxide ($Gd_2O_3;Eu^{3+}$) phosphors have been prepared by combustion method using urea[H$_2$NCONH$_2$] or carbohydrazide[H$_2$NNHCONHNH$_2$] as fuel materials in a preheated furnace at 500$^{\circ}C$. The phosphors obtained were fired at 1200$^{\circ}C$ for 3 hours to get better luminescent properties. The combustion method used was found to be a simple and fast method for the preparation of fine-sized particles. The influence of the fuel/oxidant (urea or carbohydrazide/nitrate) mole ratio on the phosphor has been investigated and the optimum values for various parameters have been determined. By this method, phosphor that has better brightness and smaller size particles than that obtained by conventional method has been prepared.d has been prepared.

• Smart Structures and Systems
• /
• v.10 no.3
• /
• pp.193-207
• /
• 2012

New insights into our previously proposed hybrid-type method for vibration control are highlighted in terms of energy analysis, such as the assessment of energy efficiency and system stability. The hybrid method improves the bang-bang active method by combining it with an energy-recycling approach. Its simple configuration and low energy-consumption property are quite suitable especially for isolated structures whose energy sources are strictly limited. The harmful influence of the external voltage is assessed, as well as its beneficial performance. We show a new chattering prevention approach that both harvests electrical energy from piezoelectric actuators and eliminates the displacement-offset of the equilibrium point of structures. The amount of energy consumption of the hybrid system is assessed qualitatively and is compared with other control systems. Experiments and numerical simulations conducted on a 10-bay truss can provide a thorough energy-efficiency evaluation of the hybrid suppression system having our energy-harvesting system.

• Nuclear Engineering and Technology
• /
• v.48 no.2
• /
• pp.559-571
• /
• 2016

This paper studies the feasibility of renewable energy as a substitute for nuclear and energy by considering Korean customers' willingness to pay (WTP). For this analysis, we use the contingent valuation method to estimate the WTP of renewable energy, and then estimate its value using ordered logistic regression. To replace nuclear power and fossil energy with renewable energy in Korea, an average household is willing to pay an additional 102,388 Korean Won (KRW) per month (approx. US $85). Therefore, the yearly economic value of renewable energy in Korea is about 19.3 trillion KRW (approx. US $16.1 billion). Considering that power generation with only renewable energy would cost an additional 35 trillion KRW per year, it is economically infeasible for renewable energy to be the sole method of low-carbon energy generation in Korea.