• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.1
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• pp.9-21
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• 2016

Nowadays various methods for energy saving have been studied in IP networks. This paper suggests a 2-phase OSPF routing method for energy saving on IP networks having various energy profiles and analyzes its characteristics. The phase-1 of the routing is an OSPF routing method considering the energy cost of devices besides existing metrics to minimize energy consumption. In the phase-2 of the routing, it makes core nodes go into sleep sate for energy saving and reroutes the paths affected by sleeping core nodes. At this time, we confirm that the characteristics of mean delay and energy efficiency can be satisfied by limiting an allowable hop number in the reroute paths, and utilization rate of nodes and links for assuring energy saving and network-level QoS. Since the efficiency of energy saving and delay characteristics differ according to selection methods of core nodes to go into sleep state, it is that the a method of core node selection based on MP(minimum_path) is more excellent than others in terms of network-level QoS and energy saving in IP networks.

• Journal of Ocean Engineering and Technology
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• v.26 no.3
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• pp.1-5
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• 2012

A complex energy saving device has been developed for middle class vessels. The propulsive performance of the developed device is described through a model test. The pre-swirl stator, which recovers the rotational energy of the propeller slipstream, is a well-known energy saving device for large vessels. The pre-swirl stator for a large vessel is usually cast as a part of the stern frame and has a high cost. The manufacture of a cast stator for an existing vessel is almost impossible. The complex device that was developed can be fitted on astern frame by welding. The model tests show a 4-6% efficiency gain for middle class vessels with the developed appendages compared to those with bare hulls.

• Journal of Korea Multimedia Society
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• v.13 no.6
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• pp.890-900
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• 2010

The Bayesian networks methods provide an efficient tool for performing information fusion and decision making under conditions of uncertainty. This paper proposes Bayes estimators for the system effectiveness in energy saving of the wireless sensor networks by use of the Bayesian method under the non-informative prior knowledge about means of active and sleep times based on time frames of sensor nodes in a wireless sensor network. And then, we conduct a case study on some Bayesian estimation models for the system energy saving effectiveness of a wireless sensor network, and evaluate and compare the performance of proposed Bayesian estimates of the system effectiveness in energy saving of the wireless sensor network. In the case study, we have recognized that the proposed Bayesian system energy saving effectiveness estimators are excellent to adapt in evaluation of energy efficiency using non-informative prior knowledge from previous experience with robustness according to given values of parameters.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.793-794
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• 2013

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.369-376
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• 2021

The International Maritime Organization has developed the Energy Efficiency Design Index, an index related to carbon dioxide emissions, to enforce regulations on newly built ships. In this study, a new type of energy-saving device called the ring stator was used for 158k crude oil carriers, whose hull form was developed as a very thin after-body hull to reduce the resistance by delaying separation. The Energy-Saving Device (ESD) particularly involving the duct, is not adapted to the thin-after body hull form-like container ship. This new ring stator was developed considering these characteristics. A parametric study was conducted through Computational Fluid Dynamics (CFD) analysis using the Star-CCM+ program, and approximately 3.4 % improvement in propulsion efficiency was achieved. Further optimization investigations and experimental studies should be conducted in the future.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.6
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• pp.419-427
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• 2015

Recently Energy Saving Device has been developed actively due to the regulation of the EEDI. This Energy Saving Device which is newly developed is integrated duct and stator. This paper verified performance of the Energy Saving Device through CFD. The experimentation to find the best pitch angle of each blade of the stator designed has been conducted. The angle of incidence of the duct has been obtained through the measurement of the wake. The experimentation has been carried out with and without Energy Saving Device. The efficiency increase was through these two experiments.

• KIEAE Journal
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• v.17 no.2
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• pp.13-20
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• 2017

Meteorological data is one of the important factors in the calculation of building energy demand. The purposes of this study are to review the limitations of the typical meteorological data of ECO2 program and to create the new typical meteorological data and then analyze the building energy demands for additional regions which are not included in the existing 13 region in the ECO2 program. The extended typical meteorological data to a total of 33 regions were based on IWEC(International Weather for Energy Calculations) data files and were created in the form applicable to the building energy efficiency rating certification system. As a result of comparing the heating energy demands of a representative region with the surrounding regions in each of five regions in Korea, the variance of Cv(RMSE) ranged from 36% to 344% and MBE ranged from -32% to 190% for the whole regions. This suggests that the difference of heating energy demand may vary greatly depending on the region where the meteorological data is used and the meteorological data of more detailed regions is needed for reliable calculation of building energy demand.

• Environmental and Resource Economics Review
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• v.25 no.2
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• pp.299-320
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• 2016

This study estimates an energy efficiency of 16 metropolitans and provinces in Korea, and measures potential energy-saving and carbon emission reduction using a non-radial data envelopment analysis method. Based on energy mix scenarios, this study also evaluates the impact of changes in energy structural adjustment on a regional environmental performance. The empirical results show that, on average, 12.70% of energy consumption and 13.73% of carbon emission can be reduced by improvement in energy efficiency, and low efficiency of oil usage in metropolitan cities is a major source of the inefficiency. Furthermore, it is found that energy mix policy should be considered to achieve an extra energy-saving and carbon reduction.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.9
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• pp.85-96
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• 2010

The recent environmental protection trend requires more strict energy saving, therefore every transportation system should reduce energy consumption to the minimum value. High-efficiency operation system, energy saving and $CO_2$ emissions shall be addressed as important issues in railway system. These issues are the most essential factors of railway, compared to major public transportation system. Recently, saving energy in the electric railway system has been studied. The efficient use of regenerated energy is considered to save energy. Namely, Using regenerative energy is that to store the energy generated during braking and discharge it again when a vehicle accelerates. Reusing energy stores and discharges energy, consequently enables a complete exchange of energy between vehicles, even if they are not braking and accelerating at precisely the same time, as is most frequently the case in everyday service. This paper analyzes effects of energy saving and $CO_2$-cut by using regenerative energy of electric vehicles.

• Journal of Energy Engineering
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• v.20 no.1
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• pp.8-12
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• 2011

For reducing greenhouse gas emissions, the short-term strategy is of existing energy-efficient appliances to facilitate the spread of energy efficiency improvements to improve energy efficiency, energy saving projects that will include investments to enable. R&D is at the core of the long-term strategy. To reduce energy demand, the equipments and processes improved energy efficiency should be developed. In terms of energy supply, the policies for greenhouse gas reduction is to replace fossil fuels by expanding the supply of renewable energy such as solar, wind, geothermal, biomass and nuclear power as nearly zero-emission of greenhouse gas. In terms of energy consumption, measures to reduce greenhouse gas emissions is in line with the policy for efficiency improvement. The buildings & work-site of high-energy consumption in the building & Industry sectors, should implement a policy to strengthening the voluntary agreement on energy-saving facilities and expand to invest in energy saving facilities.