• Journal of Advanced Navigation Technology
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• v.20 no.5
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• pp.408-416
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• 2016

This study designed a ship energy efficiency monitoring system based on a ship application system that provides maritime services by utilizing data collected onboard, and a ship-land integration system for integrated management and exchange of maritime data. The ship energy efficiency monitoring system was developed as a Windows application program and designed to use file based EDI communications. Its main functions include route planning to minimize fuel consumption, monitoring of energy consumption and gas emissions, analysis of ship energy efficiency and other data analysis. The system has been successfully implemented in actual ships.

• Journal of Communications and Networks
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• v.9 no.4
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• pp.473-481
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• 2007

Energy efficiency is one of the most critical concerns for wireless sensor networks. By allowing sensor nodes in close proximity to cooperate in transmission to form a virtual multiple-input multiple-output(MIMO) system, recent progress in wireless MIMO communications can be exploited to boost the system throughput, or equivalently reduce the energy consumption for the same throughput and BER target. However, these cooperative transmission strategies may incur additional energy cost and system overhead. In this paper, assuming that data collectors are equipped with antenna arrays and superior processing capability, energy efficiency of relevant traditional and cooperative transmission strategies: Single-input-multiple-output(SIMO), space-time block coding(STBC), and spatial multiplexing(SM) are studied. Analysis in the wideband regime reveals that, while receive diversity introduces significant improvement in both energy efficiency and spectral efficiency, further improvement due to the transmit diversity of STBC is limited, as opposed to the superiority of the SM scheme especially for non-trivial spectral efficiency. These observations are further confirmed in our analysis of more realistic systems with limited bandwidth, finite constellation sizes, and a target error rate. Based on this analysis, general guidelines are presented for optimal transmission strategy selection in system level and link level, aiming at minimum energy consumption while meeting different requirements. The proposed selection rules, especially those based on system-level metrics, are easy to implement for sensor applications. The framework provided here may also be readily extended to other scenarios or applications.

• KIEAE Journal
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• v.16 no.5
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• pp.39-45
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• 2016

Purpose: The purpose of this study is to analyze the energy saving and cost benefit analysis of the Low-income Energy Efficiency Treatment Program supported by KOREF(Korea Energy Foundation). This program was launched in 2007 and performs building energy retrofit for the low-income and energy poverty houses. Method: Energy simulation and cost benefit analysis were accomplished for the low-income detached houses. The structure of detached house was a lot og block structure, wood frame (single glass) and concrete roof. Baseline model of the low-income detached houses was proposed. Result: Annual heating energy consumptions were decreased by about 3.2% with the window system replacement(Case 1), 9.3% with reinforcement of insulation(Case2), and 12.5% with both(Case 3) compared to those of baseline model. The construction cost will be recouped within 5 years for the Case 1, 3 years for the Case 2, and 3 years for the Case 3. Case 3 was the most cost beneficient construction method in the analyzed cases in this study.

• Journal of Energy Engineering
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• v.24 no.3
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• pp.115-121
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• 2015

This paper presents the introduction plan of the renewable energy in innovation city. The introduction plan to make the condition of innovation city best should consider the economical efficiency, the quality of life and the sustainable development. The design of balanced city is demanded to build environment friendly and sustainable city. Energy efficient buildings should be designed to deal with the energy efficiency and environment problem. Therefore, in this paper, we analyze the energy efficiency and provide the method to introduce the renewable energy system, in various buildings. As a result, the renewable energy plans of each innovation city are suggested and analyzed.

• Journal of the Korean Solar Energy Society
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• v.21 no.1
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• pp.11-20
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• 2001

In this paper described common MPPT(Maximum Power Point Tracking) control algorithm; Constant Voltage Control, P&O(Perturbation and Observation), IncCond(Incremental Conductance), and investigated it's efficiency. Through simulation and efficiency evaluation, analyze the steady/transient states characteristics and efficiency of control algorithms respectively. Also, To high-efficiency proposed Two-mode MPPT control for improve on the existing control algorithm. Moreover, this paper suggested a topology for MPPT measuring efficiency and a method of examination.

• Journal of ILASS-Korea
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• v.29 no.1
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• pp.1-6
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• 2024

This paper is a numerical analysis study for evaluating the energy efficiency of electric vehicles. Currently, the methods for testing and evaluating the energy consumption efficiency of electric vehicles have limitations such as resources and time. Therefore, there is a need for research on developing models to predict the energy consumption efficiency of electric vehicles. In this study, a numerical analysis research is conducted to predict the energy efficiency of electric vehicles using a vehicle dynamics numerical analysis model. To validate the accuracy of the simulation model, it is compared the results of dynamometer tests with the simulation results and used the Unified Diagnostic Services (UDS) protocol to acquire internal data from the electric vehicle. It is ensured the reliability of the simulation model by comparing data such as motor speed, battery voltage, current, state of charge (SOC), regenerative braking power generation, and total driving distance of the test vehicle with dynamometer test data and simulation model results.

• Journal of Internet of Things and Convergence
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• v.7 no.3
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• pp.9-14
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• 2021

This paper discovers the energy loss factors through the insulation diagnosis of houses or buildings, and proposes directions for energy efficiency improvement. The energy efficiency factor of a building consists of insulation diagnosis, thermal bridge diagnosis, window diagnosis, airtight diagnosis, and equipment diagnosis. Among the residents and facilities in the energy welfare blind spot, an energy efficiency diagnosis was conducted for one senior citizen building located in Naju-si, Jeollanam-do, and energy efficiency diagnosis was conducted after insulation was installed. Energy measurement, diagnosis and analysis were performed using the IoT-based integrated wired/wireless energy diagnosis platform, Energy Finder. As a result of comparison, an overall energy saving rate of 16.38% was achieved. Annual heating energy consumption per unit area decreased from 333.51kWh before construction to 277.35kWh after construction, and annual cooling energy consumption per unit area decreased from 5.51kWh before construction to 5.22kWh after construction. The annual primary energy consumption per unit area decreased from 464.52kWh before construction to 403.69kWh after construction, and the annual energy cost was reduced from 3,063,307.14 won before construction to 2,641,072.49 won after construction. The additional improvement work is needed on the standards affecting energy efficiency other than insulation.

• ETRI Journal
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• v.33 no.3
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• pp.299-309
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• 2011

Energy consumption is a key issue in body sensor networks (BSNs) since energy-constrained sensors monitor the vital signs of human beings in healthcare applications. In this paper, packet size optimization for BSNs has been analyzed to improve the efficiency of energy consumption. Existing studies on packet size optimization in wireless sensor networks cannot be applied to BSNs because the different operational characteristics of nodes and the channel effects of in-body and on-body propagation cannot be captured. In this paper, automatic repeat request (ARQ), forward error correction (FEC) block codes, and FEC convolutional codes have been analyzed regarding their energy efficiency. The hop-length extension technique has been applied to improve this metric with FEC block codes. The theoretical analysis and the numerical evaluations reveal that exploiting FEC schemes improves the energy efficiency, increases the optimal payload packet size, and extends the hop length for all scenarios for in-body and on-body propagation.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.2046-2047
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• 2007

This paper is about the energy efficiency calculation of operating electric motors in production facilities. The most important 1st step to efficient operation of plants is the evaluation of the energy efficiency of the production facilities in that plant. Through this procedure, we can decide that which facilities i.e. induction motors, in this paper, should do maintenance or not. There are mainly 2 types of energy which are used in production facilities, the one is electric energy and the other is heat energy but in order to make calculation simple, in this paper, we are only focusing on electric energy, efficiency and energy loss of the electric motors under operation conditions. As a case study, we chose electric motors in a certain process in a production facilities, and calculated efficiency and loss by using measured data.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.6
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• pp.552-560
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• 2008

In 1997, Korean government established the National Energy and Resources Plan, which targeted from 1997 to 2005 with strategic energy technology development. At the end of 2005, Korean government built a New National Energy and Resources Plan preparing for upcoming 10 years from 2006 until 2015 based on energy technology trees comparing with the previous plan, which based on the energy R&D projects. In this research, we prioritize the relative preferences and efficiency by an AHP/DEA CCR-I and BCC-I integrated model approach considering scale efficiency for well focused R&D and efficiency of developing Greenhouse Gas technologies as an extended research from a view point of econometrics as an extended research.