• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.5
• /
• pp.2003-2021
• /
• 2020

Today's computer systems are widely integrated with CPU and GPU to achieve considerable performance, but energy consumption of such system directly affects operational cost, maintainability and environmental problem, which has been aroused wide concern by researchers, computer architects, and developers. To cope with energy problem, we propose a task-scheduling framework to reduce energy under performance constraint by rationally allocating the tasks across the CPU and GPU. The framework first collects the estimated energy consumption of programs and performance information. Next, we use above information to formalize the scheduling problem as the 0-1 knapsack problem. Then, we elaborate our experiment on typical platform to verify proposed scheduling framework. The experimental results show that our proposed algorithm saves 14.97% energy compared with that of the time-oriented policy and yields 37.23% performance improvement than that of energy-oriented scheme on average.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.19 no.4
• /
• pp.27-38
• /
• 2023

The Government the Republic of Korea is showing a lot of interest in net zero-energy buildings (NZEBs) to reduce energy consumption of buildings and to promote green growth policy in construction sector. The application of building passive technologies and renewable energies is essential to achieving NZEBs. Green remodeling reinforced the insulation of the exterior walls and roofs of the buildings and replaced high-efficiency windows and doors. In this study, the energy performance before and after green remodeling applied in a detached house was comparatively analyzed for baseline scenario and three different ones, ALT 1, ALT 2 and ALT 3. A building modeling and simulation software (DesignBuilder V7.0) with EnergyPlus (V9.4) calculation engine was used to calculate the energy demand and energy consumption for each scenario. Based on the calculation results of the building's energy demand for baseline, it was determined that the target building required more heating energy than cooling energy. The simulation results also showed that the implementation of building envelope performance improvement technologies (ALT 1) could notably decrease the heating energy consumption of the building. After the remodeling (ALT 1), the source energy consumption per unit floor area was assessed to be reduced by 65.2%, compared to prior remodeling of 338.7 kWh/m² -y. Meanwhile, ALT 2 can achieve energy savings of 67.7% and ALT 3 can achieve savings of 73.1%. Following completion of the remodeling project, actual construction costs, and on-site measurements and verification results will be gathered and compared with the simulation results. Additionally, economic analysis including construction costs and payback period will be conducted using actual site data.

• Journal of the Architectural Institute of Korea Planning & Design
• /
• v.34 no.11
• /
• pp.105-112
• /
• 2018

Global environmental problems are growing, and the importance of buildings with high energy consumption has been emphasized. In Korea, the Ministry of Land, Transport and Maritime Affairs has been promoting the mandatory zero energy building since 2020, and guidelines related to the zero energy building have been developed. In addition, based on the "Energy-saving Design Criteria for Buildings" of the "Green Building Promotion Act" in Korea, the standards for energy-saving design are specified and the energy saving plan is written. Besides, the 'Energy-saving construction standards for eco-friendly houses' also specify insulation, machinery, equipment, and sunshade. Also, there is little consideration about the cost such as construction cost and material cost which should be considered important in the construction stage. Therefore, this study aims at analysis of building type and energy performance versus materials for energy saving building design considering energy performance in planning aspect of initial design stage. In this study, because the variables can not be neglected in this study, it is selected as the lecture facility of the 'K' university campus building which can consider the remaining factors except the passive design element as the control variable, Energy performance analysis.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.16 no.2
• /
• pp.61-68
• /
• 2020

Nuclear power plants have a lower cost of power generation, and they are more eco-friendly than other power generation plants. Also, we need to prepare nuclear plant accidents because of their severe damage. In the event of a safety accident, such as a radiation leak, by applying a wireless sensor network to a nuclear power plant, many sensor nodes can be used to monitor radiation and transmit information to an external base station to appropriately respond to the accident. However, applying a wireless sensor network to nuclear power plants requires routing protocols that consider the sensor network size and bypass obstacles such as plant buildings. In general, the hierarchical-based routing protocols are efficient in energy consumption. In this study, we look into the problems that may occur if hierarchical-based routing protocols are applied to nuclear power plants and propose improved routing protocols to solve these problems. Simulation results show that the proposed routing protocol is more effective in energy consumption than the existing LEACH protocol.

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.2353-2355
• /
• 2010

Since the efforts in transportation for counteracting Climate Change have been enhanced, it is necessary to reduce GHG emissions from railroad construction. The aim of this study was to develop the calculation method of GHG emissions at the step of railroad construction. Main emission source was the energy consumption from the used heavy equipments. Firstly, GHG inventory including equipments list, energy consumption, and work load was established with the detailed process using standard for the unit cost of construction. Also, the energy consumption of heavy equipments during track construction at A site was collected to compare with the field data. As a result, the GHG emissions between the estimated and the field were a little different, which was caused by the inaccurate field data. Therefore, it is important to manage data efficiently for the calculation of GHG emissions in the field of railroad construction.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.45 no.3
• /
• pp.75-85
• /
• 2008

The DBMS are widely used in embedded systems. The flash memory is used as a storage device of a embedded system. The optimizer of existing database system assumes that the storage device is disk. There is overhead to overwrite on flash memory unlike disk. The block of flash memory should be erased before write. Due to this reason, query optimization model based on disk does not adequate for flash-aware database. Especially embedded system should minimize the consumption of energy, but consumes more energy because of excessive erase operations. This paper proposes new energy based cost model of embedded database and shows the comparison between disk based cost model and energy based cost model.

• Journal of Information Processing Systems
• /
• v.14 no.2
• /
• pp.396-417
• /
• 2018

GR-tree and query aggregation techniques have been proposed for spatial query processing in conventional spatial query processing for wireless sensor networks. Although these spatial query processing techniques consider spatial query optimization, time query optimization is not taken into consideration. The index reorganization cost and communication cost for the parent sensor nodes increase the energy consumption that is required to ensure the most efficient operation in the wireless sensor node. This paper proposes itinerary-based R-tree (IR-tree) for more efficient spatial-temporal query processing in wireless sensor networks. This paper analyzes the performance of previous studies and IR-tree, which are the conventional spatial query processing techniques, with regard to the accuracy, energy consumption, and query processing time of the query results using the wireless sensor data with Uniform, Gauss, and Skew distributions. This paper proves the superiority of the proposed IR-tree-based space-time indexing.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.22 no.10
• /
• pp.719-726
• /
• 2010

In this paper, the appropriate thermal storage time of an air-conditioning system with slab thermal storage was considered by use of summer measurement values. Two standards of heat extraction rate and criterion function were established as the standard that evaluates appropriateness. When heat extraction rate was a standard, zero hour and seven hours were obtained as appropriate thermal storage time, in the case of evaluation by energy consumption and running cost individually. Also, when criterion function was a standard, the difference between energy consumption and running cost was small, it was because the weight function to room air temperature deviation was much bigger than heat extraction rate.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.29 no.5
• /
• pp.86-93
• /
• 2015

Recently, ESS became efficient device to stabilize electric power supply system with the development SG related technology. In fact. there are some constraints to supply ESS, because of the high cost and required space, but rapid technology development for ESS will make it more useful soon. So, through this paper, we analyzed the benefit and demand effect when the battery is applied the building based on the measured energy consumption. After that, we got the conclusion that there is a volume limit in ESS application, in a benefit view point. And we realized that there is a demand violation, and the Cost-based BEMS is the best solution to enhance the effect of ESS application.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.10a
• /
• pp.257-258
• /
• 2015

Korean power consumption of the electrical supply problems due to excess demand is repeated every year, the interest in energy increasing social and personal cost has been subject to the number of ways to reduce this cost increases. Automatic doors and automatic door installation market is increasing every year and frequently, when used in general commercial and communal porch consumption based on average 300 times a day power is 70[W] degree is a monthly average usage is about 50.4[KW]. The level can not ignore the power consumption due to switching frequency is large. In this paper, by converting the energy to be discarded in the automatic doors to the inverter and the regenerative energy and to develop control systems for power regeneration to reduce the power consumption by utilizing automatic contact auxiliary power.