• Journal of Korean Physical Therapy Science
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• v.15 no.1
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• pp.21-28
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• 2008

The purposes of this study are to quantify energy expenditure by measuring oxygen consumption while performing occupational therapy activities most commonly used for adult hemiplegia patients, to recommend a optimal dosage of exercise by comparing energy expenditure according to the recovery stage, and to suggest a precaution in the treatment of patients with cardiac disorders. According to Brunnstrom recovery stages in hand function, subjects were allocated to group I(3rd and 4th Brunnstrom recovery stages) and group II(5th and 6th Brunnstrom recovery stages). Outcome measures included oxygen consumption, energy expenditure rate, and heart rate during each activity and in recovery period after the activity. Occupational activities including sanding activity, putty activity, and skateboard activity were carried out for all patients. In sanding and putty activities, there were significant differences of oxygen consumption and energy expenditure during the activity between groupⅠandⅡ(p<0.05), but there were not significant differences of oxygen consumption, energy expenditure and heart rate in the recovery period(p>0.05). In skateboard activity, there were no significant differences in oxygen consumption, energy expenditure and heart rates between the two groups during the activity and in the recovery period(p>0.05). The findings indicates that cardiovascular demands for basic activities usually peformed for a treatment may be depended on the physical recovery of patients with hemiplegia. Therefore, therapeutic activities for patients should be selected with the great care.

• Journal of Electrochemical Science and Technology
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• v.9 no.1
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• pp.37-43
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• 2018

In order to improve current efficiency and decrease energy consumption in the electrosynthesis of ammonium persulfate, electrolytic properties of four cation exchange membranes, namely, the $JCM-II^{(R)}$ membrane, $Nafion^{(R)}$ 324 membrane CMI-$7000^{(R)}$ membrane and a self-made perfluorosulfonic ion exchange membrane (PGN membrane) were investigated using a sintered platinized titanium anode and a Pb-Sb-Sn alloy cathode in a self-made electrolytic cell. The effect of cell voltage and electrolyte flow rate on the current efficiency and the energy consumption were investigated. The results indicated that the PGN membrane could improve current efficiency to 94.85% and decrease energy consumption to $1119kWh\;t^{-1}$ (energy consumption per ton of the ammonium persulfate generated) under the optimal operating conditions and the highest current efficiency of the $JCM-II^{(R)}$ membrane, $Nafion^{(R)}$ 324 membrane and CMI-$7000^{(R)}$ membrane were 80.73%, 77.76% and 73.22% with their lowest energy consumption of $1323kWh\;t^{-1}$, $1539kWh\;t^{-1}$ and $2256kWh\;t^{-1}$, respectively. The PGN membrane has the advantages of high current efficiency and energy power consumption and has sufficient mechanical strength with the reinforced mesh. Therefore the PGN membrane will has good value in popularization in the industrial electrosynthesis of ammonium persulfate in the future.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.3
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• pp.451-458
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• 2022

In Korea, five major ports have been designated as sulfur oxide emission control areas to reduce air pollutant emissions, in accordance with Article 10 of the "Special Act on Port Air Quality" and Article 32 of the "Ship Pollution Prevention Regulations". As regulations against vessel-originated air pollutants (such as PM, CO2, NOx, and SOx) have been strengthened, the Ministry of Oceans and Fisheries(MOF) enacted rules that newly built public ships should adopt eco-friendly propulsion systems. However, particularly in diesel-electric hybrid propulsion systems,the demand for precise control schemes continues to grow as the fuel saving rate significantly varies depending on the control strategy applied. The conventional Power Take In-Power Take Off(PTI - PTO) mode control adopts a rule-based strategy, but this strategy is applied only in the low-load range and PTI mode; thus, an additional method is required to determine the optimal fuel consumption point. The proposed control method is designed to optimize fuel consumption by applying the equivalent consumption minimization strategy(ECMS) to the PTI - PTO mode by considering the characteristics of the specific fuel oil consumption(SFOC) of the engine in a diesel-electric hybrid propulsion system. To apply this method, a specific fishing vessel model operating on the Korean coast was selected to simulate the load operation environment of the ship. In this study, a 10.2% reduction was achieved in the MATLAB/SimDrive and SimElectric simulation by comparing the fuel consumption and CO2 emissions of the ship to which the conventional rule-based strategy was applied and that to which the ECMS was applied.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.4991-4996
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• 2010

Clustering method in wireless sensor network is the technique that forms the cluster to aggregate the data and transmit them at the same time that they can use the energy efficiently. Even though cluster group model is based on clustering, it differs from previous method that reducing the total energy consumption by separating energy overload to cluster group head and cluster head. In this thesis, I calculate the optimal cluster group number and cluster number in this kind of cluster group model according to threshold of energy consumption model. By using that I can minimize the total energy consumption in sensor network and maximize the network lifetime. I also show that proposed cluster group model is better than previous clustering method at the point of network energy efficiency.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.2
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• pp.128-135
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• 2008

EGR(exhaust gas recirculation) is considered as a most effective method to reduce the NOx emissions. But high EGR tolerance is always pursued not only for its advantages of the pumping loss reduction and fuel economy benefit in Gasoline-Hybrid engine. However, the occurrence of excessive cyclic variation with high EGR normally prevents substantial fuel economy improvements from being achieved in practice. Therefore, the optimum EGR rate should be carefully determined in order to achieve low fuel consumption and low exhaust emission. In this study, 2 liters gasoline engine with E-EGR system was used to investigate the effects of EGR on fuel efficiency, combustion stability, engine performance and exhaust emissions. With optimal EGR rates, the fuel consumption was improved by 4%. This improvement was achieved while a reduction in NOx emissions of 75% was accomplished. Increase of EGR gas temperature causes the charge air temperature to affect the knock phenomenon and moreover, the EGR valve lift changes for the same control signal.

• Journal of the Optical Society of Korea
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• v.19 no.1
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• pp.13-21
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• 2015

In recent years energy consumption has become a main concern for network development, due to the exponential increase of network traffic. Potential energy savings can be obtained from a load-adaptive scheme, in which a day can be divided into multiple time periods according to the variation of daily traffic patterns. The energy consumption of the network can be reduced by selectively turning off network components during the time periods with light traffic. However, the time segmentation of daily traffic patterns affects the energy savings when designing multiperiod logical topology in optical wavelength routed networks. In addition, turning network components on or off may increase the overhead of logical topology reconfiguration (LTR). In this paper, we propose two mixed integer linear programming (MILP) models to design the optimal logical topology for multiple periods in IP-over-WDM networks. First, we formulate the time-segmentation problem as an MILP model to optimally determine the boundaries for each period, with the objective to minimize total network energy consumption. Second, another MILP formulation is proposed to minimize both the overall power consumption (PC) and the reconfiguration overhead (RO). The proposed models are evaluated and compared to conventional schemes, in view of PC and RO, through case studies.

• Korean Journal of Animal Reproduction
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• v.22 no.1
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• pp.43-50
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• 1998

The effect of oxygen tension on embryonic development in co-culture was evaluated from the standpoint of the reduction of dissolved oxygen concentration by the oxygen consumption of feeder cells. Three co-culture systems using bovine oviductal epitherial cells (BOEC), African green monkey kidney cells (Vero cells) or buffalo rat liver cells (BRLC) have been compared in terms of development of bovine embryos derived from oocytes matured and fertilized in vitro. Among the co-cultured embryo, Vero cells su, pp.rted the highest developmental rate (29%) and the other two showed the similar rates. When the co-cultures were incubated in three different oxygen tension such as 5, 10, 20% oxygen atmosphere, embryos co-cultured with Vero cells at 10%-O2 resulted in the highest percentage of development. From the measurement of oxygen consumption of feeder cells, BRLC consumed 1.38　10-10 mg-O2/min/cell which was higher than 0.94　10-10 and 0.26　10-10mg-O2/min/cell for Vero cells and BOEC, respectively. Based on the oxygen consumption data, the phenomena of optimum oxygen tension required in embryo development in vitro has been analyzed, and we suggested that gas phase oxygen concentration, oxygen consumption rate of feeder cells and the number of feeder cells should be considered for the design of optimal co-culture system for effective fertilization of embryos in vitro.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.7
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• pp.2914-2935
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• 2016

With the increasing popularization of cloud computing, how to reduce physical energy consumption and increase resource utilization while maintaining system performance has become a research hotspot of virtual machine deployment in cloud platform. Although some related researches have been reported to solve this problem, most of them used the traditional heuristic algorithm based on greedy algorithm and only considered effect of single-dimensional resource (CPU or Memory) on energy consumption. With considerations to multi-dimensional resource utilization, this paper analyzed impact of multi-dimensional resources on energy consumption of cloud computation. A multi-dimensional resource constraint that could maintain normal system operation was proposed. Later, a novel virtual machine deployment method (NVMDM) based on improved particle swarm optimization (IPSO) and Euclidean distance was put forward. It deals with problems like how to generate the initial particle swarm through the improved first-fit algorithm based on resource constraint (IFFABRC), how to define measure standard of credibility of individual and global optimal solutions of particles by combining with Bayesian transform, and how to define fitness function of particle swarm according to the multi-dimensional resource constraint relationship. The proposed NVMDM was proved superior to existing heuristic algorithm in developing performances of physical machines. It could improve utilization of CPU, memory, disk and bandwidth effectively and control task execution time of users within the range of resource constraint.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.968-971
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• 2009

TFT-LCD display system is nowadays one of power-hungry components in portable products; technique of power reduction is thus essential for production of mobile phone. In this work, we minimize the display power, using computationally intelligent statistical methodology. Compared with a conventional design, 68.474% reductions on the current consumption could be obtained for a 2.2-inch of TFT-LCD display system of mobile phone. The total power consumption of the display system consisting of the backlight system and current consumption of display panel is thus successfully reduced form 68.305mW to 64.06mW (about 6.215% reductions).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9B
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• pp.1322-1329
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• 2010

As body sensor network (BSN) research becomes mature, the need for managing power consumption of sensor nodes has become evident since most of the applications are designed for continuous monitoring. Real time Electrocardiograph (ECG) analysis on sensor nodes is proposed as an optimal choice for saving power consumption by reducing data transmission overhead. Smart sensor nodes with the ability to categorize lately detected ECG cycles communicate with base station only when ECG cycles are classified as abnormal. In this paper, ECG classification algorithms are described, which categorize detected ECG cycles as normal or abnormal, or even more specific cardiac diseases. Our Euclidean distance (ED) based classification method is validated to be most power efficient and very accurate in determining normal or abnormal ECG cycles. A close comparison of power efficiency and classification accuracy between our ED classification algorithm and generalized linear model (GLM) based classification algorithm is provided. Through experiments we show that, CPU cycle power consumption of ED based classification algorithm can be reduced by 31.21% and overall power consumption can be reduced by 13.63% at most when compared with GLM based method. The accuracy of detecting NSR, APC, PVC, SVT, VT, and VF using GLM based method range from 55% to 99% meanwhile, we show that the accuracy of detecting normal and abnormal ECG cycles using our ED based method is higher than 86%.