• Journal of Digital Convergence
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• v.14 no.8
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• pp.261-267
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• 2016

In this paper, we studied the range-free localization algorithm between sensor nodes based on the Radical Line for sensor networks. Routing in wireless sensor networks should reduce the overall energy consumption of the sensor network, or induce equivalent energy consumption of all the sensor nodes. In particular, when the amount of data to send more data, the energy consumption becomes worse. New methods have been proposed to address this. So as to allow evenly control the overall energy consumption. For this, the paper covers designing a localization algorithm that can obtain the location information of the peripheral nodes with fewer operations. For the operation of the algorithm is applicable Radical Line. The experimental environment is windows 7, the Visual C ++ 2010, MSSQL 2008. The experimental results could be localized to perform an error rate of 0.1837.

• Journal of Biosystems Engineering
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• v.35 no.1
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• pp.15-20
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• 2010

Tractor PTO output and fuel consumption rate under the korean paddy and various paddy operations were measured and analyzed, in which all the measurements were accomplished by the OECD tractor test codes and the collected information will be utilized for defining tractor energy efficiency class and its test methods. Tractor PTO performance tests were conducted under full-load, part-load and various engine RPMs with part-load at the engine laboratory, while the paddy operations were dry land plowing, wet and dry land rotary tilling and wet land preparation under various soils. As a whole, the rated tractor outputs were ranged from 17% to 100% in the various tillage and land preparation operations, however, the loads for the paddy operations of 1,700 to 2,000 rpm were very close to the OECD tractor load distribution thus it would be appropriate to adopt OECD tractor test codes to measure energy consumption efficiency of tractor.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.7C
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• pp.654-662
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• 2009

Video streams for mobile video streaming can be encoded to fit the available network bandwidth by controlling three factors: temporal resolution, spatial resolution, and picture quality. The controlling of picture quality by modifying the quantization parameter (QP) is most widely used. In this paper, we demonstrate that reducing the spatial resolution adaptively can be more efficient in terms of picture quality and energy consumption in low bit-rate environment, and present a model to find the optimal spatial resolution for the available bandwidth. Adaptive spatial resolution control scheme is especially effective when the bandwidth between the video server and the mobile device varies considerably with time, and when the mobile device is sensitive to energy consumption. Our scheme can improve the picture quality by approximately O.5dB and reduce energy consumption by more than 50% compared to the conventional video coding in low bit-rate environment.

• Applied Chemistry for Engineering
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• v.30 no.1
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• pp.95-101
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• 2019

The cremation rate of Korea in 2016 was 82.7% which is four times greater than 20.5% in 1994. As increasing the cremation rate gradually, it cause a shortage of cremation facilities resulting in building more cremation facilities to meet the increasing inquiries on cremation or a large amount of fuels for the longer operation of the crematory. In this study, the crematory system optimizing its thermal efficiency characteristics and also responding to increasing inquiries on cremation was proposed in order for solving such problems, In particular, the heat flow characteristics including a heat transfer coefficient by performing a simulation using computational fluid dynamics (CFD) was investigated. The CFD model was validated with on-site experiments for a cremation facility. As a result of the simulation, the fuel consumption decreased nearly 25% and residence time increased in the main combustor. Also, the improved crematory was constructed with an expanded combustor, heat exchanger, second combustion air system, refractory and insulation material. From on-site experiments, the energy consumption was saved to approximately 54.4%, while the burning time reduced nearly 20 minutes.

• Journal of Advanced Navigation Technology
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• v.11 no.4
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• pp.423-429
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• 2007

Since the wireless smart card has played a main role in the identification security application for the building access; this research has its purpose to improve the performance of the smart card system and aims to offer more convenient to user. The contactless cards do not require insertion into a card reader and can work up to centimeters away from the reading device. To be able to cope with this performance the controlling of power consumption through the adaptive modulation and error control is needed. This paper addresses a forward error control (FEC) scheme with the adaptive Reed-Solomon code rate and an M-ary frequency shift keying (M-FSK) modulation scheme with the varying symbol size M over the link. The result of comparing energy efficiencies of adaptive error correction and adaptive modulation to other various static schemes shows to save over 50% of the energy consumption.

• Journal of Korean Society of Transportation
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• v.5 no.2
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• pp.19-35
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• 1987

Transportation energy saving is a national concern because all national petroleum energy is imported. A number of intersections are operating as semi-protected intersections, which have left-turn signal but not exclusive left-turn lanes, because of limited roadways in urban areas. Since the traffic signal methods for the intersections having left-turn signal/lanes cannot be applied to the semi-protected intersection, it is needed to develop a new technique. The purpose of this study was to develop a traffic signal timing method at semi-protected intersections for energy saving and to computerize the method for the practical use. A probability model which could estimate left-turn utilization factors of through traffic during green signal was developed based on field studies. Employing the factors, macro-models to estimate vehicular average delay and proportions of vehicles stopped at the semiprotected intersections were developed. The calculated values of the delay model agreed well with the simulated values of a simulation model using SLAM Ⅱ, a simulation language. Using the two models and the idling fuel consumption rate and the excess fuel consumption per stop-go speed change of vehicles. a traffic signal timing method at semi-protected intersections for energy saving was developed and computerized. The method can be used for other measures of effectiveness such as minimum delay, minimum stop ratio, etc.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.983-989
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• 2012

IEEE 802.3az LPI mechanism allows an Ethernet link to reduce power consumption by entering a low-power sleeping mode and letting some components being powered off when there is no data to be transmitted through the link. However, if small amount of packets are being sent periodically, such a mechanism can not obtain energy efficiency due to a high overhead caused by excessive mode transitions. In this paper, we propose an enhanced LPI mechanism which can perform state transition adaptively based on the traffic characteristics on transport layer and network status. This simulation result shows that proposed mechanism improves energy efficiency than LPI mechanism with respect to energy consumption rate for various traffic loads.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.11 no.4
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• pp.7-13
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• 2015

The efficiency, reliability and performance of any heat pump unit can only be ascertained after it has been tested and rated. For this reason, specific facilities, equiped with testing plants are built. Heat pump calorimeter is the facilities used by most of these testing facilities in their rating and certification process. The ultimate function of calorimeters is to, control and maintain the constant standard test conditions (indoor/outdoor entering temperatures and flow rate etc) during testing period. In this study, the test standards of heat pump unit and the structure of the calorimeter are surveyed. In addition, this study analyzes the total energy consumption of a water to water heat pump calorimeter. Heat pump calorimeter consumed much energy to excute the heat pump tests. The energy consumption of the calorimeter was higher than the heat pump unit, and it was increased as the heat pump unit capacity decreased.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.11
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• pp.813-822
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• 2012

In this study, the multizone simulation for biosafety of BSL3 lab. and energy simulation are carried out simultaneously by using linked model of CONTAM and TRNSYS. In BSL3 lab., annual energy consumption is approximately five to ten times more than the magnitude of the office building. This is because required air change rate is extremely large and it is difficult to maintain room pressure difference efficiently. To maintain pressure difference between laboratory rooms through sealing condition of doors and proper airflow control is significant. In this study, to predict indoor environment of the BSL3 lab.(Influenza A research lab.), the multizone simulation for four kinds of biohazard scenario is also performed as part of risk assessment. Multizone and energy simulation results by using linked model show that these approaches are used as a tool for the energy efficient design and operation method for the safer BSL3 lab. facilities.

• Journal of Energy Engineering
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• v.19 no.3
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• pp.171-176
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• 2010

Using a hydrogen blended compressed natural gas (HCNG) as a fuel for IC engines has a significant meaning in terms of achieving a reduction of automotive exhaust emissions as well as preparing for an upcoming hydrogen economy by constructing hydrogen infrastructure. In addition, a HCNG engine has higher thermal efficiency than a CNG engine, which is another advantage that makes HCNG fuel considered as a future alternative for natural gas. Therefore, in this study, idling operation of a 11 litre HCNG bus engine was investigated in terms of fuel consumption rate and emissions characteristics. The results show that fuel consumption rate was decreased more than 20% by use of HCNG and all the emissions were significantly reduced in idling condition.