• Journal of Environmental Impact Assessment
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• v.25 no.5
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• pp.307-318
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• 2016

This research examines the impacts of urban population growth on per capita $CO_2$ emissions with particular focus on the interaction effect between urbanization and income levels. Employing the Panel Fixed Effects model together with the Pooled LS and Panel GLS models, the research reported here analyzes the relevant data on 84 countries. The statistical results show a nonlinear(an inverted-U) relationship between urbanization and per capita $CO_2$ emissions; that is, while the urban agglomeration leads to increases in per capita $CO_2$ emissions for low income countries, this adverse impact does not hold true for high income countries. The research findings can contribute to addressing broad issues of urban compactness and patterns of energy consumption that should be considered by those concerned about the sustainable urban development.

• Journal of the Korean Institute of Gas
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• v.13 no.1
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• pp.28-33
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• 2009

Natural gas is the world's most plentiful combustible fuel, abundantly acailable in all continent. A fuel injector designed specifically for low energy density gaseous fuels has been developed. The injector incorporates design features that are necessary to optimize the performance for fuels such as CNG, LNG. Gaseous fuel injectors have a decisive influence upon starting performance, driveability, fuel consumption and exhaust emissions. A gaseous fuel injector has been developed to cope with the considerably larger volume flow rates and the developed gaseous fuel injector could be used at heavy duty natural gas engine. The static flow of injectors at various inlet pressure was directly proportional and the controllability showed great performance.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.12
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• pp.913-917
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• 2009

Flash memories have asymmetric I/O costs for read and write in terms of latency and energy consumption. However, the ratio of these costs is dependent on the type of storage. Moreover, it is becoming more common to use two flash memories on a system as an internal memory and an external memory card. For this reason, buffer cache replacement algorithms should consider I/O costs of device as well as possibility of reference. This paper presents WWCLOCK(Write-Weighted CLOCK) algorithm which directly uses I/O costs of devices along with recency and frequency of cache blocks to selecting a victim to evict from the buffer cache. WWCLOCK can be used for wide range of storage devices with different I/O cost and for systems that are using two or more memory devices at the same time. In addition to this, it has low time and space complexity comparable to CLOCK algorithm. Trace-driven simulations show that the proposed algorithm reduces the total I/O time compared with LRU by 36.2% on average.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2779-2785
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• 2009

Among the livestock, chickens are raised because of the merit ingested protein in low-priced cost of production and are primary livestock increased the consumption of meat. The factors of influencing condition, odor is the most important factor. Odor substances are ammonia, amines, hydrogen sulfide and mercaptan which come from night soil. Livestock are prevented from rearing by means of these odor substances. Though the henhouse is heated using hot air type heater in the winter season, it is ventilated for the control of odor because of the increase of odor concentration. In the present work, composite catalytic system combined the existing facilities(hot air type heater) with catalytic system was developed, it could controled odor and hazardous gas using the oxidation/reduction reaction without extra operating cost. Moreover, the purpose of this work is to develop the catalysts which are cost competitive and can maximize energy efficiency. The catalysts are noble metal(Pt-Rh) and composite transition metal(Mn) type.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.2135-2140
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• 2015

In this paper, proposed a new lighting control system which can reduce power consumption compared to conventional street lamps and intelligently control the light efficiently depending on whether there is a vehicle on the street. The new lighting control system proposed by this paper detects the presence of cars by collecting and analyzing sounds generated by the movement of cars. Then, the system controls lighting of street lamps based on the above car detection information, and turns on the street lamps sequentially by transmitting the car detection information. Experimental results showed that lightings were controlled based on the presence of cars and that operations of the lamps were made by turning on the lights sequentially by determining the moving direction of cars. This system is considered a technology that can reduce energies by applying to local roads with a few cars moving or national highways where lights are always turned on with low energy efficiency.

• Journal of Korea Multimedia Society
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• v.16 no.10
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• pp.1196-1203
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• 2013

In general, the cost of transceiver for wireless network configuration is more expensive than that for wired network. However, in case of environmental management system in a tunnel, the cost can be minimized by adopting low rate tranceiver because the amount of the exchanged data for tunnel monitoring is very small. When the obtained data from sensor node is sent directly to the corresponding command node, there is no need to consider routing problem of the data transfer. However in this case, sensor nodes are required to be implemented with high power transmitter and experience high energy consumption. To tackle this problem, relay nodes can be used to transfer the data of tunnel monitoring, and suitable routing protocols for selecting optimum path are needed. Therefore, in this paper, we propose a routing algorithm and a self-configuration protocol for environment management system in tunnel.

• Nutrition Research and Practice
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• v.5 no.2
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• pp.140-149
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• 2011

This study was conducted to evaluate the rate of obesity of 212 women (age 45-60 years) in Seoul and the Kyunggi area through analysis of BMI and the dietary life factors related to obesity using a survey on dietary habits, dietary assessment, and nutrient intake. The height of the underweight group was taller than normal. The height of the obese group was equal to that of the normal group, but the weight was 8.5 kg greater than the normal group. Women in the underweight group consumed meals irregularly, and only 33.4% ate breakfast. Additionally, the rate of overeating was low in the underweight group, and milk, dairy products (yogurt, etc.), fruit, and fruit juice were consumed more than once a day. It was found that 62.1% of the women in the obese group never ate out, and the rate of eating one serving of fruit, drinking one cup of fruit juice, and eating various kinds of foods was high. The average point of women's dietary life was $21.9{\pm}2.9$, and 12.7% of all women responded that their dietary life was good. However, in the obese group, only 6.9% of the women reported that their dietary life was good. Evaluation of snacking habits revealed that the underweight group consumed a high level of carbonated drinks and ice cream, whereas for in the obese group, 24.1% of the women consumed milk and its products and 5.6% regularly consumed fast and fried foods. Evaluation of nutrient intake revealed that the consumption of energy, protein, vitamin A, vitamin $B_1$, $B_2$, $B_6$, niacin, vitamin C, and vitamin E was high in all of the groups, but the intake of folic acid in the underweight group was lower than the required level. Overall, 24.1% of the women in the obese group were found to have metabolic diseases, mostly hypertension (43%). In conclusion, a balanced diet to avoid excessive nutrient intake is needed to prevent obesity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11B
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• pp.1363-1372
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• 2011

Flooding based routing protocols are usually used to disseminate information in wireless sensor networks. Those approaches, however, require message retransmissions to all nodes and induce huge collision rate and high energy consumption. In this paper, HoGoP (Hop based Gossiping Protocol) in which all nodes consider the number of hops from sink node to them, and decide own gossiping probabilities, is introduced. A node can decide its gossiping probability according to the required average reception percentage and the number of parent nodes which is counted with the difference between its hop and neighbors' ones. Therefore the decision of gossiping probability for network topology is adaptive and this approach achieves higher message reception percentage with low message retransmission than the flooding scheme. Through simulation, we compare the proposed protocol with some previous ones and evaluate its performance in terms of average reception percentage, average forwarding percentage, and forwarding efficiency. In addition, average reception percentage is analyzed according to the application requirement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.7-13
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• 2017

A comfortable indoor environment is important considering that many hours are spent in residential or office space. A humidifier is used to control the indoor humidity. In particular, an element type humidifier has the advantage of a simple structure and low energy consumption. Two types of humidifiers - stationary or rotor - are commonly used for residential purposes. In this study, performance optimization was conducted for a rotor-type humidifying element used in a residential humidifier. The optimization included the rotation speed, water submersion depth, etc. The test range consisted of an open area to the air from 57 to 90%, rotation speed from 0.2 to 2.0 rpm, frontal air velocity from 0.5 to 2.5 m/s. The results showed that the optimal open area to air was 70%. On the other hand, the effects of the rotation speed on the moisture transfer rate was negligible. On the other hand, the pressure drop increased with increasing rotation speed. As the frontal air velocity increased, both the moisture transfer rate and pressure drop increased. The humidification capacity of the present element was 0.08 ~ 0.31 kg/hr. A comparison of the data with the theoretical results was made.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.5
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• pp.430-433
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• 2017

This paper presents a S/C/X-band LNA MMIC with resistive feedback structure in 0.25 um GaN HEMT process. The GaN devices have advantages as a high output power device having high breakdown voltage, energy band gap and stability at high temperature. Since the receiver using the GaN device with high linearity can be implemented without a limiter, the noise figure of the receiver can be improved and the size of receiver module can be reduced. The proposed GaN LNA MMIC based on 0.25 um GaN HEMT device is achieved the gain of > 15 dB, the noise figure of < 3 dB, the input return loss of > 13 dB, and the output return loss of > 8 dB in the S/C/X-band. The current consumption of GaN LNA MMIC is 70 mA with the drain voltage 20 V and the gate voltage -3 V.