• 대한전기학회논문지:전력기술부문A
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• 제54권6호
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• pp.274-283
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• 2005

This paper presents a new method to derive energy function based on vector product. Using this method, an energy function to consider transfer conductances and capacitors is derived. Then we recommend a voltage collapse criteria to predict the voltage collapse in power systems by using the energy margin derived by the proposed energy function. This energy function is applied to a 2-bus power system reflecting transfer conductances and capacitors. We show that the energy function derived based on vector product can be applied in order to analyze power system stability and the energy margin can be utilized as a criterion of voltage collapse by simulation for the 2-bus system.

• 설비공학논문집
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• 제21권5호
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• pp.311-318
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• 2009

In previous study, a new allocation methodology of common cost on multi-product have been suggested. The aim of this study is to suggest the methodology that allocates an environment pollution cost including carbon emission cost to each cost of multi-product. For this study, a supposed multi-energy system composed of twenty kinds of systems was made. The multi-energy system produces eighteen kinds of outputs that are electricity, steam, hot water, chilled water, ice, warm air, and cooling air from seven kinds of energy source that are LNG, coil, geothermal energy, sun heat, hydrogen, bio-mass, and waste. The new methodology was applied to the multi-energy system in order to allocate the environment pollution cost to each production cost, and twenty seven equations were induced. From this result, it is concluded that this methodology can estimate each unit cost and allocate each cost flow in any product of any energy system.

• 한국태양에너지학회 논문집
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• 제37권5호
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• pp.85-99
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• 2017

New and Renewable Energy Equipment Certification program has been integrated into the KS(Korean Industrial Standards) certification system as of July 29, 2015. This study is to determine whether the KS certification requirement has had a positive effect on corporate performance (e.g. quality improvement, financial result, customer satisfaction) within those that had already acquired the New and Renewable Energy Equipment KS certification. As a result, among the requirements for the KS certification, quality management, product management, and product testing have a positive impact on product quality improvement, and product testing has shown a positive influence on customer satisfaction. Although requisite for the KS certification did not have a significant effect on financial outcome such as increase in revenue, it has shown to have positive consequence to some extent on those firms that newly obtained the certification.

• International Journal of Internet, Broadcasting and Communication
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• 제11권1호
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• pp.89-96
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• 2019

The purpose of this study is to investigate Nest Labs (Nest)'s business strategy. The activities based on strategic choices for monetizing connected product are investigated. Nest's capacity and functionality is to offer a seamless integration of devices, platforms, and services and the "Works with Nest" offers an ecosystem fulfilling the needs of different partners. For monetizing customer data, Nest provides a seamless customer experience supported by product incentives. Nest introduces open APIs to connect its connected products to the wider Internet of things (IoT) and open to "If This, Then That." The Nest app controls them from one single place. Nest partners with 32 energy providers as of 2017 and they provide energy from renewable and non-renewable energy sources. Nest also creates a sales channels in direct and indirect route and expands is business model to other industries such as home-rental service, 'AirBnB' to help consumers become more energy-efficient at home.

• Journal of Computational Design and Engineering
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• 제1권4호
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• pp.256-265
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• 2014

Energy efficiency is an essential consideration in sustainable manufacturing. This study presents the car fender-based injection molding process optimization that aims to resolve the trade-off between energy consumption and product quality at the same time in which process parameters are optimized variables. The process is specially optimized by applying response surface methodology and using non-dominated sorting genetic algorithm II (NSGA II) in order to resolve multi-object optimization problems. To reduce computational cost and time in the problem-solving procedure, the combination of CAE-integration tools is employed. Based on the Pareto diagram, an appropriate solution is derived out to obtain optimal parameters. The optimization results show that the proposed approach can help effectively engineers in identifying optimal process parameters and achieving competitive advantages of energy consumption and product quality. In addition, the engineering analysis that can be employed to conduct holistic optimization of the injection molding process in order to increase energy efficiency and product quality was also mentioned in this paper.

• 한국안전학회지
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• 제7권3호
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• pp.35-42
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• 1992

Ignition energy effects of concentration of mixed gas In closed cylindrical vessel(1, 832㎤) are studied. The ignition energy ranged from 25 Joule to 110 Joule, and hidrogen and methane gases were used for flammable gas at stoichiometric condition with oxygen gas and nitrogen gas (N2) was for inert gas, which concentration was maximum 60% . The explosion pressure, temperature, concentration of product gases were calculated. It is found that - The explosion pressure and explosion velocity increase with ignition energy. - The gradience of explosion velocity with ignition energy is steeper than explosion pressure. - The results of calculation are similiar with results of experiment. - NOx is not serious product gas for methane and hydrogen gas, but CO is serious at certain concentration for methane in asphyxiation.

• 한국분말재료학회지
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• 제15권2호
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• pp.87-94
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• 2008

In order to investigate a nitriding process of spent oxide fuel and the subsequent change in thermal properties after nitriding, simulated spent fuel powder was converted into a nitride pellet with simulated fission product elements through a carbothermic reduction process. Nitriding rate of simulated spent fuel was decreased with increasing of the amount of fission products. Contents of Ba and Sr in simulated spent fuel were decreased after the carbothermic reduction process. The thermal conductivity of the nitride pellet was decreased by an addition of fission product element but was higher than that of the oxide fuel containing fission product elements.

• Journal of Radiation Protection and Research
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• 제41권3호
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• pp.237-244
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• 2016

Background: Korea Atomic Energy Research Institute is developing a fission product transport module for predicting the behavior of radioactive materials in the primary cooling system of a nuclear power plant as a separate module, which will be connected to a severe accident analysis code, Core Meltdown Progression Accident Simulation Software (COMPASS). Materials and Methods: This fission product transport (COMPASS-FP) module consists of a fission product release model, an aerosol generation model, and an aerosol transport model. In the fission product release model there are three submodels based on empirical correlations, and they are used to simulate the fission product gases release from the reactor core. In the aerosol generation model, the mass conservation law and Raoult's law are applied to the mixture of vapors and droplets of the fission products in a specified control volume to find the generation of the aerosol droplet. In the aerosol transport model, empirical correlations available from the open literature are used to simulate the aerosol removal processes owing to the gravitational settling, inertia impaction, diffusiophoresis, and thermophoresis. Results and Discussion: The COMPASS-FP module was validated against Aerosol Behavior Code Validation and Evaluation (ABCOVE-5) test performed by Hanford Engineering Development Laboratory for comparing the prediction and test data. The comparison results assuming a non-spherical aerosol shape for the suspended aerosol mass concentration showed a good agreement with an error range of about ${\pm}6%$. Conclusion: It was found that the COMPASS-FP module produced the reasonable results of the fission product gases release, the aerosol generation, and the gravitational settling in the aerosol removal processes for ABCOVE-5. However, more validation for other aerosol removal models needs to be performed.

• 전기전자학회논문지
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• 제23권3호
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• pp.878-882
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• 2019

XOR(exclusive-OR)-XNOR(exclusive NOR) 회로는 고 성능 산술 연산에 필요한 4-2 압축 회로(4-2 compressor)의 기본 구성 요소이다. 본 논문에서는 에너지 효율이 우수한 XOR-XNOR 회로를 제안한다. 제안한 회로는 임계 경로의 내부 기생 캐패시턴스를 감소시켜 전파 지연 시간을 감소시켰으며, 모든 입력 조합의 경우에 완벽한 출력 값을 가지며 8개의 트랜지스터로 설계되었다. 기존 회로와 비교하여 제안한 회로는 전파 지연 시간이 14.5% 감소하였으며, 전력 소모는 1.7% 증가하였다. 따라서 전력 소모와 지연 시간의 곱 (power-delay product: PDP)과 에너지와 지연 시간의 곱 (energy-delay product: EDP) 각각 13.1%, 26.0% 감소하였다. 제안한 회로는 0.18um CMOS 표준공정을 이용하여 설계하였으며 SPICE 시뮬레이션을 통해 타당성을 입증하였다.

• 한국경영공학회지
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• 제23권4호
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• pp.73-86
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• 2018

Most electric products produced during the manufacturing process are produced after design and mass production under a given control standard. In particular, the development phase should present the criteria for the production process by setting appropriate limits based on the performance being targeted. Even if the standard of performance is set considering the performance of the process, measuring the performance of the product after actual production results will cause nonconformities with the expected results. Among the performance of electrical products, Energy standards represented by energy consumption efficiency continue to be of importance, and are mandatory standards that correspond to national standards in most countries. Therefore, statistical quality control of these standards shall basically have a large number of test equipment for each product, ensure sufficient test time and continuous sampling of product samples. In the end, companies that produce and sell electric appliances are striving to control mass production at a great cost, but this is not acceptable. This study presents basic characteristics of the energy efficiency of electrical products and proposes and conducts a case study on statistical production control methods for performance variation across products under the standards about domestic and international regulations.