• Journal of Korean Institute of Architectural Sustainable Environment and Building Systems
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• v.12 no.6
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• pp.567-578
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• 2018

The purpose of this study was to evaluate condensation prevention for condensation vulnerable areas around built-in furniture of apartment buildings by applying auxiliary heating device. Recently, the condensation and mold problems of apartment buildings has been growing due to high insulation and high air-tightness performance for energy saving. Condensation at built-in furniture were generally found in winter at the of furniture's back panels, adjacent surfaces of wall, floor and ceiling. These problems are related to the weather conditions and indoor room conditions in winter. To solve these problems, auxiliary heating device was developed and could be installed. The aim of paper is to analyze the thermal environment around the built-in furniture which were applied and not applied auxiliary heating device in winter. In results, it was possible to increase the surface temperature of vulnerable areas around built-in furniture by applying auxiliary heating device, and to minimize condensation problems by using the minimum device.

• Nuclear Engineering and Technology
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• v.54 no.7
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• pp.2579-2585
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• 2022

Ceramics of quaternary garnets (Gd,Y)₃Al₂Ga₃O₁₂ doped with Ce, Tb have been fabricated and evaluated as prospective materials for indirect energy converters of α-and β-voltaic. Samples were characterized at excitation with an X-ray source and an intense 150 keV electron beam and showed good temperature stability of their emission and tolerance to irradiation. The role of X-rays accompanied the α-particle emitting in the increase of the conversion efficiency is clarified. The garnet-type structure of the matrix in the developed materials allows the production of quality crystalline mass with a light yield exceeding that of the commonly used YAG: Ce scintillator by a factor of two times.

• Nuclear Engineering and Technology
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• v.41 no.4
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• pp.381-390
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• 2009

This article provides selects of outstanding problems in computational neutron transport, with some suggested approaches thereto, as follows: i) ray effect in discrete ordinates method, ii) diffusion synthetic acceleration in strongly heterogeneous problems, iii) method of characteristics extension to three-dimensional geometry, iv) fission source and $k_{eff}$ convergence in Monte Carlo, v) depletion in Monte Carlo, vi) nuclear data evaluation, and vii) uncertainty estimation, including covariance data.

• Journal of Theoretical and Applied Mechanics
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• v.1 no.1
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• pp.1-27
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• 1995

In this paper a finite element method for free-surface problems is described. the method is based on two different forms of Hamilton's principle. To test the present computational method two specific wave problems are investigated; the dispersion relations and the nonlinear effect for the well-known solitary waves are treated. The convergence test shows that the present scheme is more efficient than other existing methods, e.g. perturbation scheme.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.249-251
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• 2011

International energy agency(IEA) consisted of OECD countries deals with international energy problems. IEA/Wind ExCo is an execution committee under IEA for the implementing agreement for co-operation in the research, development and deployment of wind energy systems. Currently 22 countries participate the committee and 11 research tasks are in progress. 11 tasks are base technology information exchange, wind energy in cold climates, offshore wind energy technology deployment, integration of wind and hydropower systems, power systems with large amounts of wind power, cost of wind energy, labelling small wind turbines, social acceptance of wind energy projects, MexNext aerodynamics and comparison of dynamic computer codes and models, offshore wind energy and wakebench. At the presentation, activities of major wind energy countries and IEA/Wind ExCo and research tasks are introduced.

• KIEAE Journal
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• v.13 no.2
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• pp.13-20
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• 2013

Today, the world energy consumption in buildings occupies more than 30%. In our country, the energy consumption in buildings also occupies 25% of the entire national energy consumption. With the increasing demand of energy saving in architectural fields, there is a more interest in low-energy construction. For these low-energy housings, our country is planning to apply the energy-saving design standards at the level of passive houses in 2017. However, there is still a limitation in energy saving only with the standards on the performance of envelope in buildings. This means that unless a building is airtight even though it was well-insulated, cooling and heating energy consumption will increase due to the infiltration and leakage. Therefore, this study aims to make a comparative analysis of airtight performance by conducting a blower door test on the housings applied with passive designs, analyze the reasons why most houses fall short of the airtightness standards, and complement the airtightness problems in the inadequate parts of the buildings in order to save building energy.

• Journal of the Korean Solar Energy Society
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• v.28 no.6
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• pp.40-47
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• 2008

The importance for energy consumptions has being emphasized because of problems of the energy and environment. Especially, education buildings among public buildings which have being emphasized the application of environment-friendly elements because of large energy consumptions. Accordingly, this study established parameters of green walls and green roofs which have ecological effects and energy savings. And then this study analyzed indoor thermal environments and energy consumptions due to green walls and green roofs through the energy simulation(Visual DOE 4.0) and the actual measurement.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.227-230
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• 2009

Currently the country's foreign energy dependence reaches approximately 97% and the total energy consumption percentage of buildings(commercial and domestic parts) reaches approximately 24%. Building energy saving by enhanced insulation will be very important issue. Therefore, the solution is required to reduce energy loss and increasing displeasure caused by excessive influx of solar energy through windows, to solve the problems like decoloration on indoor furniture an clothes by harmful ultraviolet rays, air conditioning and increased cost. This research used for commercialization and ills semination by basic information through a evaluation on insulation performance of the window of high efficiency energy equipment which can improve the insulation performance.

• Journal of Biosystems Engineering
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• v.3 no.1
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• pp.64-76
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• 1978

A dimensional supply of petroleum fuels and increased competition for petroleum products has made the conservation of energy in grain drying an important cost and management factor. Research on solar grain drying is directed toward utilization of a renewable energy source as an alternative to petroleum fuels for drying. There are many technical and economic problems in accepting and adopting solor energy as a new energy source for grain drying. The purpose of this study are to assess the state of the art of solar grain drying and to find out the problems by reviewing literatures available. The results obtained may be summarized as follows; 1.It may be considered that the weather conditions in October of Korea was satisfactory for the forced natural air and solar heated air drying. 2. Solar energy is considered more applicable to low-temperature, In-storage drying systems than to high-temperature, high-speed drying systems. In-storage drying systems require low levels of heat input. The costs of collector systems to provide low temperature are considerably cheaper than for high-temperature systems. 3. Tubular type collector made of polyvinyle film seems to be the most practical at this stage of development and black-painted bare-plate collectors mounted on the outside of a typical, round, low-temperature drying bin can supply an appreciable amount of the energy efficiently needed for low-temperature grain drying at a lower cost. 4. All of the grains in solar drying tests was successfully dried up to safe storaged moisture levels without significant spoilage. Drying rates with solar system were faster than natural air drying systems, and usually a little slower than similar low-temperature electric drying systems. 5. Final grain moisture levels were lower in solar tests than in natural air tests, and generally higher than in tests with continuous heated air. 6. Savings of energy by use of solar collectors ranged from 23% to 55%, compared to the natural and electric ileated air drying systems. However, total drying cost effectiteness tvas not significant. Therefore, it is desirable that solar grain dry-ing sIFstems tvhich could be suitable for multiple heating purposes on farms shouldbe developed. 7. Supplemental heat with solar radiation did little to reduce air flow requirementsbut refuced drying time and increased the p\ulcornerobability of successful drying duringdrying poriod.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.187-192
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• 2017

In dense deployments of sensor nodes in Wireless Sensor Networks, the MAC protocol has challenges to solve problems such as reducing delivery delay and reducing energy consumption. To solve these problems lots of protocols are suggested. This paper proposed a sensor nodes' residual energy based wake-up control mechanism, in which each node decides whether it wakes up or stays in sleep mode to save energy consumption by reducing unnecessary idle listening. The main idea of the wake-up control mechanism is to save node's energy consumption. The proposed wake-up control mechanism is based on the RI-MAC protocol, which is one of the receiver-initiated MAC protocols. A receiver node in the proposed mechanism periodically wakes up and broadcasts a beacon signal based on the energy status of the node. A receiver node also adjusts wake-up period based on the traffics. Results have shown that the proposed MAC protocol outperformed RI-MAC protocol in the terms of energy consumption.