• Journal of Satellite, Information and Communications
• /
• v.7 no.2
• /
• pp.1-7
• /
• 2012

In recent years, importance of environmental protection and energy resources has increased. Therefore, eco - friendly consumption patterns is rapidly increased. Accordingly, efficient energy consumption technology is noted in a variety of industries. Smart grid technology can improve energy efficiency by using IT technology. Among them, the demand response is an critical factor in the smart grid. In this paper, we present basic concept of smart grid and demand response. In addition, we present demand response technology and its application examples.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.6
• /
• pp.2709-2734
• /
• 2020

The growing demand to make wireless data services 5G compatible has necessitated the development of an energy-efficient approach for an effective new wireless environment. In this paper, we first propose a cognitive sensor node (CSN) based game theory for deriving energy via a primary user-transmitted radio frequency signal. Cognitive users' time was segmented into three phases based on a time switching protocol: energy harvest, spectrum sensing and data transmission. The proposed model chooses the optimal energy-harvesting phase as the effected factor. We further propose a distributed energy-harvesting model as a utility function via pricing techniques. The model is a non-cooperative game where players can increase their net benefit in a selfish manner. Here, the price is described as a function pertaining to transmit power, which proves that the proposed energy harvest game includes Nash Equilibrium and is also unique. The best response algorithm is used to achieve the green connection between players. As a result, the results obtained from the proposed model and algorithm show the advantages as well as the effectiveness of the proposed study. Moreover, energy consumption was reduced significantly (12%) compared to the benchmark algorithm because the proposed algorithm succeeded in delivering energy in micro which is much better compared to previous studies. Considering the reduction and improvement in power consumption, we could say the proposed model is suitable for the next wireless environment represented in 5G.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.8
• /
• pp.1505-1510
• /
• 2008

In large-scale wireless sensor networks, the deployed nodes cannot be replaced or recharged after first deployment. Also, dead nodes maγ lead to the partition of whole networks. While performing data dissemination under a battery power constraint, energy efficiency is a key design factor of routing protocol. As a solution for the efficient data dissemination, in this paper, we propose a protocol namely Hierarchical Data Dissemination (HDD) which provides scalable and efficient data delivery to multiple sources and mobile sinks. HDD uses the facts that sink nodes are central gathering Points and source-centric data forwarding paths are constructed and it is maintained with two-tier communications. The performance of HDD is compared with TTDD about the energy consumption, data delivery time and data success ration. The extensive simulation results show that HDD Routing Protocol outperforms TIDD by more than $1.5{\sim}3times$ on energy consumption.

• KIEAE Journal
• /
• v.11 no.3
• /
• pp.19-30
• /
• 2011

This study examined apartment residents' energy-lifestyle, and their energy consumption patterns by energy-lifestyle. The major findings are as follow: 1)In order to identify energy lifestyle, three dimensions - value of life, energy consuming behavior and energy awareness - were defined by literature reviews, and each dimension was tested to define components. 2)The scores of the 14 factors that were defined by factor analysis on the three dimensions of the energy lifestyle were subject to cluster analysis, and then lifestyle was categorized into five groups. G1 is very negative, and indifferent to energy waste or saving at home. G2 is passively carrying out energy saving activities at home, only within their comfort. G3 is aware of energy saving, and more actively keeping energy saving behavior in their everyday lives, while they also show energy waste behavior at the same time. G4 is particularly indifferent to energy costs, and presenting energy squandering behaviors. G5 is better aware of energy saving than other groups, and carrying out energy saving behaviors in their everyday lives. This study would be of help to establish energy saving management and education plans in apartments.

• KIEAE Journal
• /
• v.13 no.5
• /
• pp.51-57
• /
• 2013

Energy saving starts by knowing how much energy is being consumed. A building factor is easier than any other things in energy saving. Since, especially, it is closely connected with user's space-use-patterns and manager's utility-operation-style. An energy metering system lets building users know about energy consumption pattern in buildings and measure energy in real time. Development and materialization of metering systems need more careful plans, so that they depend on a demand of individual facilities and available infrastructures they used to use. But, so far, there is no guidelines how to install metering systems. This paper suggested how to install meters and researched a method for how to analyze by using metered data. For that, Green Building in KIER is used as a test bed. As the results, nevertheless the smallest number of meters is basically one for the whole building energy measuring, it is too limited in analysis. So we needed to add the sort of fuel and utility types and found that it depends on all cases. For this reasons, a guideline should be created in order to install meters as soon as possible. It would be suggest a way to save more energy in building factor.

• Korean Journal of Community Nutrition
• /
• v.8 no.3
• /
• pp.270-279
• /
• 2003

Middle and high school students in Korea spend a lot of time at school. In other words, many Korean teenagers spend most of their time studying, and have little time for other activities, such as physical workouts. Fewer physical activities, and consumption of many snacks, etc. may lead to overweight or obesity in some teenagers. This study was conducted to find out the activity levels of teenagers' in order to calculate their daily energy expenditures. A total of 1,192 students (461 middle school students and 731 high school students) who lives in either a city or a country area were recruited for this study. One-day Activity Diaries were collected using questionnaires and analyzed by means of SPSS /win. The participating students spent about 7 hours 24 minutes resting including sleeping; 6 hours 28 minutes studying ,4 hours 4 minutes in leisure activities , 1 hour 32 minutes in personal hygiene activities such as washing, dressing and undressing, etc., 50 minutes on transportation : and 23 minutes on household chores such as cleaning, doing the laundry, etc. The average activity factor was 1.49. That of middle school female students was the lowest at 1.47, followed by middle school male students at 1.48, high school female students at 1.49, and high school male students at 1.51. The daily energy expenditure of middle and high school male students was 2,289 kcal and 2,600 kcal, respectively. That of female students was 1,959 kcal and 2,067 kcal, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.4A
• /
• pp.450-457
• /
• 2008

One of very essential techniques for enlarging lifetime of energy-constrained wireless personal area network (WPAN) devices is energy-efficient transmission technique. If the WPAN is operated based on a TDMA protocol, the satisfaction of QoS requirements at each allocated time slot is another important factor to be considered. We therefore propose an energy-efficient transmission scheme for WPANs operating with a contention-free medium access protocol such as TDMA, as well as satisfying QoS requirement. The proposed algorithm determines the optimum combination of transmit power, physical data rate and fragment size required to simultaneously minimize the energy consumption and satisfy the required QoS in each assigned time duration, considering all the possible energy-minimization related parameters. The proposed algorithm demonstrated the improved performance results in terms of throughput and energy consumption via computer simulation.

• 한국태양에너지학회:학술대회논문집
• /
• 2012.03a
• /
• pp.286-292
• /
• 2012

In recent years, building energy has received much attention and there are many support system to reduce building energy consumption. In addition, It is clear that encouraging to energy efficiency investments can be beneficial to our society, because of the energy supply instability and higher energy price in Korea. Nevertheless, ESCO business, represent the existing building energy retrofit business, hardly has not expanded in Korea. besides, in the case of existing building, it is more difficult to achieve the energy retrofit measures than new building, due to the existing buildings have attributes such as a long life and a lots of energy factor, etc. Therefore, for activate ESCO business and expand ESCO bussiness target to small-to-medium building, it is needed to optimization of retrofitting methods for existing small-to medium buildings in Korea. this research was to derive energy retrofit methods through the energy audit and analysis performed for a small-to-medium building located in Suwon, Korea.

• KIEAE Journal
• /
• v.15 no.4
• /
• pp.5-11
• /
• 2015

Purpose: Recently, renewable energy system has been widely used to reduce the energy consumption and CO2 emission of building. A photovoltaic/thermal(PVT) system is a kind of efficient energy uses, which is combined with photovoltaic module and solar thermal collector. PVT system removes heat from PV module by through thermal fluid to raise the performance efficiency of the PV system. However, though PVT system has the merit of the improved efficiency in theoretical approach, there have been few performance analysis for PVT system using the dynamic energy simulation. In this study, in order to establish the optimum design method of this system, simulation was conducted by using individual system modules. Method: For the dynamic simulation, TRNSYS17 was used and local weather data was utilized. Furthermore, the system performance in various installation condition was calculated by case studies. Result: As a result, the amount of electric generation and heat production in each case was found by the simulation. The gap of system performance was also evident according to the installation condition.

• Journal of Biomedical Engineering Research
• /
• v.34 no.3
• /
• pp.141-147
• /
• 2013

Ultrasonic shears is currently in wide use as an energy device for minimal invasive surgery. There is an advantage of minimizing the carbonization behavior of the tissue due to the vibrational energy transfer system of the transducer by applying a piezoelectric ceramic. However, the vibrational energy transfer system has a pitfall in energy consumption. When the movement of the forceps is interrupted by the tissue, the horn which transfers the vibrational energy of the transducer will be affected. A study was performed to recognize different tissues by measuring the impedance of the transducer of the ultrasonic shears in order to find the factor of energy consumption according to the tissue. In the first stage of the study, the voltage and current of the transducer connecting portion were measured, along with the phase changes. Subsequently, in the second stage, the impedance of the transducer was directly measured. In the final stage, using the handpiece, we grasped the tissue and observed the impedance differences appeared in the transducer To verify the proposed tissue distinguishing method, we used the handpiece to apply a force between 5N and 10N to pork while increasing the value of the impedance of the transducer from 400 ${\Omega}$.. It was found that fat and skin tissue, tendon, liver and protein all have different impedance values of 420 ${\Omega}$, 490 ${\Omega}$, 530 ${\Omega}$, and 580 ${\Omega}$, respectively. Thus, the impedance value can be used to distinguish the type of tissues grasped by the forceps. In the future study, this relationship will be used to improve the energy efficiency of ultrasonic shears.