• Advances in nano research
• /
• v.15 no.6
• /
• pp.521-531
• /
• 2023

Quantum-dot cellular automata (QCA) has shown great potential in the nanoscale regime as a replacement for CMOS technology. This work presents a specific approach to static random-access memory (SRAM) cell based on 2:1 multiplexer, 4-bit SRAM array, and 32-bit SRAM array in QCA. By utilizing the proposed SRAM array, a single-layer 16×32-bit SRAM with the read/write capability is presented using an optimized signal distribution network (SDN) crossover technique. In the present study, an extremely-optimized 2:1 multiplexer is proposed, which is used to implement an extremely-optimized SRAM cell. The results of simulation show the superiority of the proposed 2:1 multiplexer and SRAM cell. This study also provides a more efficient and accurate method for calculating QCA costs. The proposed extremely-optimized SRAM cell and SRAM arrays are advantageous in terms of complexity, delay, area, and QCA cost parameters in comparison with previous designs in QCA, CMOS, and FinFET technologies. Moreover, compared to previous designs in QCA and FinFET technologies, the proposed structure saves total energy consisting of overall energy consumption, switching energy dissipation, and leakage energy dissipation. The energy and structural analyses of the proposed scheme are performed in QCAPro and QCADesigner 2.0.3 tools. According to the simulation results and comparison with previous high-quality studies based on QCA and FinFET design approaches, the proposed SRAM reduces the overall energy consumption by 25%, occupies 33% smaller area, and requires 15% fewer cells. Moreover, the QCA cost is reduced by 35% compared to outstanding designs in the literature.

• Journal of the Korean Society for Precision Engineering
• /
• v.30 no.5
• /
• pp.486-492
• /
• 2013

Energy cost has been increasing rapidly to comply with environmental regulations worldwide and the manufacturing industry who consumes more than half of the total energy needs to improve their cost competitiveness considering environmental costs. Machine tools are essential elements in manufacturing industry and efforts have been made recently to increase their energy efficiency mainly by German and Japanese machine tool builders. In this paper, trends in energy saving technology are described on the hardware and software sides of peripheral equipment of machine tools. In addition, the power consumption of a machining center is measured and analyzed to develop a software-based standby strategy for energy saving with peripheral equipment of machine tools.

• Journal of the Korean Solar Energy Society
• /
• v.30 no.1
• /
• pp.50-60
• /
• 2010

Today, the amount of energy consumption in the university campuses is huge. The effort for the energy consumption reduction in university campuses is certainly needed by the following reason; first, contribution to the greenhouse gas discharge reduction demand. Second, energy cost reduction in university campus. Third, contribution to the improvement of the social awareness as the maximum higher educational institutions. The energy consumption analysis of current situation has to be executed for the energy consumption reduction in university campus. The energy reduction possibility in which it exists in university campuses can be understood through the energy consumption analysis. And the application is possible as fundamental data of the policy establishment for the effective energy reduction in university campuses. Especially, the best way to reduce the energy consumption in university campuses that is the energy consumption reduction of buildings. Accordingly, this study derived the plans for improving the performance of energy in the university building by analyzing case study, so this study analyzed the performance of energy for the university building through VE, a program for the analysis of building energy. Based on this result, this study classified the plans improving the efficiency of energy in university building into the plan for passive control and active control respectively, and suggested some concrete plans, and finally evaluated the performance of decreasing energy consumption for each plan.

• Journal of Korean Physical Therapy Science
• /
• v.7 no.1
• /
• pp.285-294
• /
• 2000

80 persons who don't have past history of cardiopulmonary and neuromuscular disease. The results were as follow; 1. PCI(Physiological Cost Index) value without loading to ankle were significantly increased compared to 1kg, and 2kg (p<0.01). 2. Female Subjects showed more increased PCI value in without loading and lkg, 2kg loading compared to male subjects (p<0.01). 3. In every PCI condition the difference among height groups was observed (p<0.01). 4. The difference among weight groups in each PCI condition was observed (p<0.01). These results showed that energy consumption was increased according to loading on the ankle during gait so weight of orthosis or prosthesis must be considered when choosing them and during gait training with these ones.

• Proceedings of the KSME Conference
• /
• 2000.11b
• /
• pp.216-221
• /
• 2000

Most Ice making companies make simple efforts to make products and fail to introduce improvements into the system against huh cost of products. The work presented here is an implementation of ice making method to improve both energy efficiency and productivity. In this present investigation, several ice making cycles are designed and calculated to evaluate COP, ice making time and electric energy consumption. Results obtained shows that COP is improved with more efficient use of time for ice making and electric consumption. Therefore this can offer the opportunity for more efficient energy consumption and productivity in ice making.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.11 no.12
• /
• pp.5712-5728
• /
• 2017

Recently, there are many studies, that considering green wireless cellular networks, have taken the energy consumption of the base station (BS) into consideration. In this work, we first introduce an energy consumption model of multi-mode sharing BS powered by multiple energy sources including renewable energy, local storage and power grid. Then communication load requests of the BS are transformed to energy demand queues, and battery energy level and worst-case delay constraints are considered into the virtual queue to ensure the network QoS when our objective is to minimize the long term electricity cost of BSs. Lyapunov optimization method is applied to work out the optimization objective without knowing the future information of the communication load, real-time electricity market price and renewable energy availability. Finally, linear programming is used, and the corresponding energy efficient scheduling policy is obtained. The performance analysis of our proposed online algorithm based on real-world traces demonstrates that it can greatly reduce one day's electricity cost of individual BS.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.16 no.4
• /
• pp.1-8
• /
• 2020

For a central cooling system of a medical facility composed of absorption chiller and screw chiller, the study was conducted on how to minimize the energy cost. In consideration of the energy cost, the optimal operation method in which the operation method of the heat source is changed according to the size of the cooling load was derived through simulation analysis. When applying the optimal operation method, the indoor environment, energy consumption, and energy cost were analyzed and compared with the reference operation method.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2019.05a
• /
• pp.59-60
• /
• 2019

Thermal bridge on a building envelope causes additional heat loss which increases the heating energy consumption. As the higher building insulation performance is required, heat loss through thermal bridge becomes higher proportion among total building heating energy consumption. For the exterior insulation and finish system, thermal bridge between window frame and concrete wall should be constidered as one of main reasons of heat loss. In this study, the thermal bridge barrier between window frame and concrete wall(STAR) was proposed as the best practice for reducing thermal bridge. The STAR was confirmed that the use of thermal bridge barrier imporved the annual heat energy capacity by 35% or more and the innitial construction cost by 7.4% or less because of additional interior insulation against condensation. Finally the life cycle cost during 20 year by heating energy of a building reduced by 25% or more compared with the exist technology. This STAR thermal bridge barrier will be used as the main technology to improve the energy efficiency of building.

• Transactions of the Korean hydrogen and new energy society
• /
• v.33 no.3
• /
• pp.247-254
• /
• 2022

Slush hydrogen containing liquid and solid hydrogen is expected to achieve zero boil-off by suppressing boil-off gas because heat of fusion for solid absorbe the heat ingress from atmosphere. In this paper, quantitative analysis on storage cost considering specific energy consumption between 1,000 m³ class liquid hydrogen storage system with re-liquefaction and slush hydrogen storage system during equivalent zero boil off period. Even though approximately 50% of total storage capacity should be converted into solid phase during the initial cargo bunkering, total energy consumption to convert into slush hydrogen is relatively 25% less than re-liquefaction energy for boil off hydrogen during zero boil off period. That's because energy consumption of slush phase change take up only 1.8% of liquefaction energy. moreover, annual revenue requirement including CAPEX, OPEX and electric cost for slush hydrogen storage could be more reduced approximately 32.5% than those of liquid hydrogen storage and specific energy storage cost ($/kg-H₂) could also be lowered by about 41.7% compared with liquid hydrogen storage.

• Architectural research
• /
• v.19 no.4
• /
• pp.101-108
• /
• 2017

The use of the air conditioner is increasing due to the rise of the outdoor temperature during summer, and the problems of the fire and the cooling performance deterioration are caused due to lack of maintenance of the outdoor unit. In particular, overall performance of cooling system and efficiency in outdoor units have been degraded due to an intake of high-temperature outdoor air thereby increasing cooling energy and operating cost. Thus, this study aimed to increase efficiency of outdoor units by evaporating and cooling intake air through mist spray at the intake port surface in the outdoor unit. The measurements results showed that total power consumption of misting outdoor unit compared to that of conventional outdoor units was reduced by 21% approximately, and total power consumption of the entire system including pump was reduced by 16.7%. In addition, the operating cost including water use was reduced by 13.5% approximately. In summary, if a mist-spray nozzle kit is installed in air-cooled outdoor units, the reduction in the usage of cooling energy and operating cost will be achieved without replacement of existing cooling systems or a large scale of repairs.